Surgical instruments with torsion spine drive arrangements

ABSTRACT

Surgical instruments with articulatable surgical end effectors and rotary driven flexible drive members.

CROSS-REFERENCE TO RELATED APPLICATIONS

This non-provisional application claims priority under 35 U.S.C. § 120to U.S. patent application Ser. No. 17/360,133, entitled SURGICALINSTRUMENTS WITH TORSION SPINE DRIVE ARRANGEMENTS, filed Jun. 28, 2021,now U.S. Patent Application Publication No. 2022/0031313, which claimsthe benefit under 35 U.S.C. § 119(e) of U.S. Provisional PatentApplication Ser. No. 63/057,430, entitled SURGICAL INSTRUMENTS WITHTORSION SPINE DRIVE ARRANGEMENTS, filed Jul. 28, 2020, of U.S.Provisional Patent Application Ser. No. 63/057,432, entitledARTICULATION JOINT ARRANGEMENTS FOR SURGICAL INSTRUMENTS, filed Jul. 28,2020, the disclosures of which are incorporated by reference herein intheir entireties.

BACKGROUND

The present invention relates to surgical instruments and, in variousarrangements, to surgical stapling and cutting instruments and staplecartridges for use therewith that are designed to staple and cut tissue.The surgical instruments may be configured for use in open surgicalprocedures, but have applications in other types of surgery, such aslaparoscopic, endoscopic, and robotic-assisted procedures and mayinclude end effectors that are articulatable relative to a shaft portionof the instrument to facilitate precise positioning within a patient.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the various aspects are set forth withparticularity in the appended claims. The described aspects, however,both as to organization and methods of operation, may be best understoodby reference to the following description, taken in conjunction with theaccompanying drawings in which:

FIG. 1 is a perspective view of a surgical end effector portion of asurgical instrument in accordance with at least one aspect of thepresent disclosure;

FIG. 2 is a side view of the surgical end effector portion instrument ofFIG. 1 in a closed orientation;

FIG. 3 is an end view of the surgical end effector of FIG. 2 ;

FIG. 4 is a top view of the surgical end effector of FIG. 2 ;

FIG. 5 is an exploded assembly view of a portion of the surgicalinstrument of FIG. 1 ;

FIG. 6 is an exploded assembly view of an elongate shaft assembly of thesurgical instrument of FIG. 1 ;

FIG. 7 is another exploded assembly view of the elongate shaft assemblyof FIG. 6 ;

FIG. 8 is an exploded assembly view of a firing system and a rotarydrive system according to at least one aspect of the present disclosure;

FIG. 9 is a side view of a firing member and upper and lower flexiblespine assemblies of the firing system in engagement with a rotary drivescrew of the rotary drive system of FIG. 8 ;

FIG. 10 is a cross-sectional view of the firing member and upper andlower flexible spine assemblies of FIG. 9 ;

FIG. 11 is a side elevational view of the firing member and upper andlower flexible spine assemblies in engagement with the rotary drivescrew of FIG. 9 ;

FIG. 12 is a cross-sectional end view of the surgical end effector ofFIG. 4 taken along line 12-12 in FIG. 4 ;

FIG. 13 is an exploded perspective view of two adjacent upper vertebramembers of the upper flexible spine assembly of FIG. 10 ;

FIG. 14 is an exploded perspective view of two adjacent lower vertebramembers of the lower flexible spine assembly of FIG. 10 ;

FIG. 15 is a top view of a firing member and upper and lower flexiblespine assemblies in engagement with the rotary drive screw of FIG. 9 ;

FIG. 16 is a perspective view of a CV drive shaft assembly of the rotarydrive system of FIG. 8 in an articulated orientation;

FIG. 17 is a perspective view of the firing system of FIG. 8 in drivingengagement with the CV drive shaft assembly of FIG. 16 in accordancewith at least one aspect of the present disclosure;

FIG. 18 is a perspective view of a drive joint of the CV drive shaftassembly of FIG. 16 ;

FIG. 19 is a cross-sectional view of a portion of the surgicalinstrument of FIG. 4 taken along line 19-19 in FIG. 4 ;

FIG. 20 is a partial perspective view of a proximal end portion of thesurgical end effector and portions of the firing system and the rotarydrive system of the surgical instrument of FIG. 1 ;

FIG. 21 is a perspective view of the rotary drive system of the surgicalinstrument of FIG. 1 in driving engagement with the firing systemthereof in accordance with at least one aspect of the presentdisclosure;

FIG. 22 is an exploded perspective view of the rotary drive screw andthrust bearing arrangement of the firing system of FIG. 21 ;

FIG. 23 is a side view of the rotary drive screw of FIG. 22 ;

FIG. 24 is a partial cross-sectional side view of a portion of the lowerflexible spine assembly and a portion of the firing member of FIG. 21 indriving engagement with a portion of the rotary drive screw;

FIG. 25 is a perspective view of the firing member in a home or startingposition within the surgical end effector of the surgical instrument ofFIG. 1 ;

FIG. 26 is a side view illustrating the upper flexible spine assemblyand the lower flexible spine assembly of FIG. 21 in driving engagementwith the rotary drive screw after the firing member has been drivendistally from a home or starting position;

FIG. 27 is a partial cross-sectional perspective view of a portion ofthe surgical end effector, firing system and rotary drive system of thesurgical instrument of FIG. 1 according to at least one aspect of thepresent disclosure with an outer elastomeric joint assembly of anarticulation joint omitted for clarity;

FIG. 28 is another partial perspective view of a portion of the surgicalend effector, firing system and rotary drive system of FIG. 27 with anouter elastomeric joint assembly of an articulation joint and portionsof the elongate shaft assembly omitted for clarity;

FIG. 29 is a top view of the surgical end effector of FIG. 27articulated in a first direction relative to a portion of the elongateshaft assembly in accordance with at least one aspect of the presentdisclosure;

FIG. 30 is a side view of the surgical end effector of FIG. 29articulated in another direction relative to a portion of the elongateshaft assembly in accordance with at least one aspect of the presentdisclosure;

FIG. 31 is a perspective view of the surgical end effector of FIG. 29articulated in multiple planes with respect to a portion of the elongateshaft assembly in accordance with at least one aspect of the presentdisclosure;

FIG. 32 is a side elevational view of a portion of another surgicalinstrument that employs another outer elastomeric joint assembly inaccordance with at least one aspect of the present disclosure;

FIG. 33 is a partial cross-sectional perspective view of the surgicalinstrument of FIG. 32 ;

FIG. 34 is a perspective view of a portion of the outer elastomericjoint assembly of FIG. 32 ;

FIG. 35 is a cross-sectional end view of a portion of the surgicalinstrument of FIG. 19 taken along lines 35-35 in FIG. 19 ;

FIG. 36 is a cross-sectional end view of a portion of the surgicalinstrument of FIG. 19 taken along lines 36-36 in FIG. 19 ;

FIG. 37 is a partial cross-sectional view of a portion of an anvil capand an upper vertebra member of the surgical instrument of FIG. 19 inaccordance with at least one aspect of the present disclosure;

FIG. 38 is a side view of a portion of the surgical end effector of thesurgical instrument of FIG. 19 with an anvil thereof in an open positionin accordance with at least one aspect of the present disclosure andwith portions of the surgical end effector omitted for clarity;

FIG. 39 is a partial cross-sectional side view of the surgical endeffector of FIG. 38 with the anvil in an open position and the firingmember in the home or starting position in accordance with at least oneaspect of the present disclosure;

FIG. 40 is another partial cross-sectional side view of the surgical endeffector of FIG. 39 with the anvil in a partially closed position;

FIG. 41 is another partial cross-sectional side view of the surgical endeffector of FIG. 39 with the anvil in a fully closed position and thefiring member distally advancing through the surgical end effector;

FIG. 42 is a partial side elevational view of the surgical end effectorof FIG. 19 with portions thereof omitted for clarity to illustrate theanvil opening springs applying an opening motion to the anvil and withthe firing member in a home or starting position;

FIG. 43 is another partial side view of the surgical end effector ofFIG. 42 , after the firing member has moved proximally a short distanceto apply a quick closure motion to the anvil for grasping purposes;

FIG. 44 is a cross-sectional view of the surgical end effector of FIG.19 with the jaws thereof in a closed position and the firing memberthereof in a proximal-most position;

FIG. 45 is another cross-sectional view of the surgical end effector ofFIG. 44 , after the firing member has been distally advanced to theending position within the surgical end effector;

FIG. 46 is a perspective view of a portion of another surgicalinstrument;

FIG. 47 is a side elevational view of a surgical end effector of thesurgical instrument of FIG. 46 , with the jaws thereof in an openposition;

FIG. 48 is another side view of the surgical end effector of FIG. 48with the jaws thereof in a closed position;

FIG. 49 is an exploded assembly view of a portion of the surgicalinstrument of FIG. 46 ;

FIG. 50 is a perspective view of a firing member and portions of anupper flexible spine assembly and a lower flexible spine assembly of afiring system of the surgical instrument of FIG. 46 ;

FIG. 51 is a cross-sectional side view of the portions of the firingsystem depicted in FIG. 50 ;

FIG. 52 is a partial exploded assembly view of the upper flexible spineassembly and lower flexible spine assembly depicted in FIG. 51 ;

FIG. 53 is a partial cross-sectional end view of an upper portion of thefiring member depicted in FIG. 50 ;

FIG. 54 is a cross-sectional end view of the surgical end effector ofthe surgical instrument of FIG. 46 , with the jaws thereof in a closedposition;

FIG. 55 is a view of a proximal face of an annular rib member of amovable exoskeleton assembly of the surgical instrument of FIG. 46 ;

FIG. 56 is a view of a distal face of the annular rib member of FIG. 55;

FIG. 57 is a side view of the annular rib member of FIGS. 55 and 56 ;

FIG. 58 is a partial cross-sectional view of a portion of the surgicalinstrument of FIG. 46 ;

FIG. 59 is a side view of an articulation joint of the surgicalinstrument of FIG. 46 when the surgical end effector thereof is in anunarticulated position;

FIG. 60 is another side view of the articulation joint of FIG. 59 whenthe surgical end effector is in an articulated position;

FIG. 61 is partial perspective view of a portion of the surgicalinstrument of FIG. 46 with the surgical end effector omitted forclarity;

FIG. 62 is another partial perspective view of a portion of the surgicalinstrument of FIG. 46 ;

FIG. 63 is another partial perspective view of a portion of the surgicalinstrument of FIG. 46 ;

FIG. 64 is a perspective view of a CV drive shaft assembly and a portionof the elongate shaft assembly of the surgical instrument of FIG. 46 ;

FIG. 65 is another perspective view of the CV drive shaft assembly andelongated shaft assembly of FIG. 64 with a drive cover embodimentinstalled around the CV drive shaft assembly;

FIG. 66 is another perspective view of the CV drive shaft assembly andelongated shaft assembly of FIG. 64 with another drive cover embodimentinstalled around the CV drive shaft assembly;

FIG. 67 is another perspective view of the CV drive shaft assembly andelongated shaft assembly of FIG. 64 with another drive cover embodimentinstalled around the CV drive shaft assembly;

FIG. 68 is a side view of a portion of the firing system of the surgicalinstrument of FIG. 46 with the drive cover of FIG. 67 installed aroundthe CV drive shaft assembly; and

FIG. 69 is another side view of the portion of the firing system anddrive cover of FIG. 68 .

DETAILED DESCRIPTION

Applicant of the present application owns the following U.S. patentapplications that were filed on Jun. 28, 2021 and which are each hereinincorporated by reference in their respective entireties:

U.S. patent application Ser. No. 17/360,139, entitled SURGICALINSTRUMENTS WITH FIRING MEMBER CLOSURE FEATURES, now U.S. PatentApplication Publication No. 2022/0031322;

U.S. patent application Ser. No. 17/360,149, entitled SURGICALINSTRUMENTS WITH SEGMENTED FLEXIBLE DRIVE ARRANGEMENTS, now U.S. PatentApplication Publication No. 2022/0031314;

U.S. patent application Ser. No. 17/360,162, entitled SURGICALINSTRUMENTS WITH FLEXIBLE BALL CHAIN DRIVE ARRANGEMENTS, now U.S. PatentApplication Publication No. 2022/0031319;

U.S. patent application Ser. No. 17/360,176, entitled SURGICALINSTRUMENTS WITH DOUBLE SPHERICAL ARTICULATION JOINTS WITH PIVOTABLELINKS, now U.S. Patent Application Publication No. 2022/0031345;

U.S. patent application Ser. No. 17/360,192, entitled SURGICALINSTRUMENTS WITH DOUBLE PIVOT ARTICULATION JOINT ARRANGEMENTS, now U.S.Patent Application Publication No. 2022/0031350;

U.S. patent application Ser. No. 17/360,197, entitled SURGICALINSTRUMENTS WITH COMBINATION FUNCTION ARTICULATION JOINT ARRANGEMENTS,now U.S. Patent Application Publication No. 2022/0031323;

U.S. patent application Ser. No. 17/360,199, entitled METHOD OFOPERATING A SURGICAL INSTRUMENT, now U.S. Patent Application PublicationNo. 2022/0031315;

U.S. patent application Ser. No. 17/360,211, entitled SURGICALINSTRUMENTS WITH DUAL SPHERICAL ARTICULATION JOINT ARRANGEMENTS, nowU.S. Patent Application Publication No. 2022/0031324;

U.S. patent application Ser. No. 17/360,220, entitled SURGICALINSTRUMENTS WITH FLEXIBLE FIRING MEMBER ACTUATOR CONSTRAINTARRANGEMENTS, now U.S. Patent Application Publication No. 2022/0031320;

U.S. patent application Ser. No. 17/360,244, entitled ARTICULATABLESURGICAL INSTRUMENTS WITH ARTICULATION JOINTS COMPRISING FLEXIBLEEXOSKELETON ARRANGEMENTS, now U.S. Patent Application Publication No.2022/0031346; and

U.S. patent application Ser. No. 17/360,249, entitled SURGICALINSTRUMENTS WITH DIFFERENTIAL ARTICULATION JOINT ARRANGEMENTS FORACCOMMODATING FLEXIBLE ACTUATORS, now U.S. Patent ApplicationPublication No. 2022/0031351.

Numerous specific details are set forth to provide a thoroughunderstanding of the overall structure, function, manufacture, and useof the embodiments as described in the specification and illustrated inthe accompanying drawings. Well-known operations, components, andelements have not been described in detail so as not to obscure theembodiments described in the specification. The reader will understandthat the embodiments described and illustrated herein are non-limitingexamples, and thus it can be appreciated that the specific structuraland functional details disclosed herein may be representative andillustrative. Variations and changes thereto may be made withoutdeparting from the scope of the claims.

The terms “comprise” (and any form of comprise, such as “comprises” and“comprising”), “have” (and any form of have, such as “has” and“having”), “include” (and any form of include, such as “includes” and“including”) and “contain” (and any form of contain, such as “contains”and “containing”) are open-ended linking verbs. As a result, a surgicalsystem, device, or apparatus that “comprises,” “has,” “includes” or“contains” one or more elements possesses those one or more elements,but is not limited to possessing only those one or more elements.Likewise, an element of a system, device, or apparatus that “comprises,”“has,” “includes” or “contains” one or more features possesses those oneor more features, but is not limited to possessing only those one ormore features.

The terms “proximal” and “distal” are used herein with reference to aclinician manipulating the handle portion of the surgical instrument.The term “proximal” refers to the portion closest to the clinician andthe term “distal” refers to the portion located away from the clinician.It will be further appreciated that, for convenience and clarity,spatial terms such as “vertical”, “horizontal”, “up”, and “down” may beused herein with respect to the drawings. However, surgical instrumentsare used in many orientations and positions, and these terms are notintended to be limiting and/or absolute.

References to items in the singular should be understood to includeitems in the plural, and vice versa, unless explicitly stated otherwiseor clear from the text. Grammatical conjunctions are intended to expressany and all disjunctive and conjunctive combinations of conjoinedclauses, sentences, words, and the like, unless otherwise stated orclear from the context. Thus, the term “or” should generally beunderstood to mean “and/or”, etc.

Recitation of ranges of values herein are not intended to be limiting,referring instead individually to any and all values falling within therange, unless otherwise indicated herein, and each separate value withinsuch a range is incorporated into the disclosure as if it wereindividually recited herein. The words “about,” “approximately” or thelike, when accompanying a numerical value, are to be construed asindicating a deviation as would be appreciated by one of ordinary skillin the art to operate satisfactorily for an intended purpose. Similarly,words of approximation such as “approximately” or “substantially” whenused in reference to physical characteristics, should be construed tocontemplate a range of deviations that would be appreciated by one ofordinary skill in the art to operate satisfactorily for a correspondinguse, function, purpose or the like.

The use of any and all examples, or exemplary language (“e.g.,” “suchas,” or the like) provided herein, is intended merely to betterilluminate the embodiments and does not pose a limitation on the scopeof the embodiments. No language in the specification should be construedas indicating any unclaimed element as essential to the practice of theembodiments.

Various exemplary devices and methods are provided for performinglaparoscopic and minimally invasive surgical procedures. However, thereader will readily appreciate that the various methods and devicesdisclosed herein can be used in numerous surgical procedures andapplications including, for example, in connection with open surgicalprocedures. As the present Detailed Description proceeds, the readerwill further appreciate that the various instruments disclosed hereincan be inserted into a body in any way, such as through a naturalorifice, through an incision or puncture hole formed in tissue, etc. Theworking portions or end effector portions of the instruments can beinserted directly into a patient's body or can be inserted through anaccess device that has a working channel through which the end effectorand elongate shaft of a surgical instrument can be advanced.

It is common practice during various laparoscopic surgical procedures toinsert a surgical end effector portion of a surgical instrument througha trocar that has been installed in the abdominal wall of a patient toaccess a surgical site located inside the patient's abdomen. In itssimplest form, a trocar is a pen-shaped instrument with a sharptriangular point at one end that is typically used inside a hollow tube,known as a cannula or sleeve, to create an opening into the body throughwhich surgical end effectors may be introduced. Such arrangement formsan access port into the body cavity through which surgical end effectorsmay be inserted. The inner diameter of the trocar's cannula necessarilylimits the size of the end effector and drive-supporting shaft of thesurgical instrument that may be inserted through the trocar.

Regardless of the specific type of surgical procedure being performed,once the surgical end effector has been inserted into the patientthrough the trocar cannula, it is often necessary to move the surgicalend effector relative to the shaft assembly that is positioned withinthe trocar cannula in order to properly position the surgical endeffector relative to the tissue or organ to be treated. This movement orpositioning of the surgical end effector relative to the portion of theshaft that remains within the trocar cannula is often referred to as“articulation” of the surgical end effector. A variety of articulationjoints have been developed to attach a surgical end effector to anassociated shaft in order to facilitate such articulation of thesurgical end effector. As one might expect, in many surgical procedures,it is desirable to employ a surgical end effector that has as large arange of articulation as possible.

Due to the size constraints imposed by the size of the trocar cannula,the articulation joint components must be sized so as to be freelyinsertable through the trocar cannula. These size constraints also limitthe size and composition of various drive members and components thatoperably interface with the motors and/or other control systems that aresupported in a housing that may be handheld or comprise a portion of alarger automated system. In many instances, these drive members mustoperably pass through the articulation joint to be operably coupled toor operably interface with the surgical end effector. For example, onesuch drive member is commonly employed to apply articulation controlmotions to the surgical end effector. During use, the articulation drivemember may be unactuated to position the surgical end effector in anunarticulated position to facilitate insertion of the surgical endeffector through the trocar and then be actuated to articulate thesurgical end effector to a desired position once the surgical endeffector has entered the patient.

Thus, the aforementioned size constraints form many challenges todeveloping an articulation system that can effectuate a desired range ofarticulation, yet accommodate a variety of different drive systems thatare necessary to operate various features of the surgical end effector.Further, once the surgical end effector has been positioned in a desiredarticulated position, the articulation system and articulation jointmust be able to retain the surgical end effector in that locked positionduring the actuation of the end effector and completion of the surgicalprocedure. Such articulation joint arrangements must also be able towithstand external forces that are experienced by the end effectorduring use.

A variety of surgical end effectors exist that are configured to cut andstaple tissue. Such surgical end effectors commonly include a first jawfeature that supports a surgical staple cartridge and a second jaw thatcomprises an anvil. The jaws are supported relative to each other suchthat they can move between an open position and a closed position toposition and clamp target tissue therebetween. Many of these surgicalend effectors employ an axially moving firing member. In some endeffector designs, the firing member is configured to engage the firstand second jaws such that as the firing member is initially advanceddistally, the firing member moves the jaws to the closed position. Otherend effector designs employ a separate closure system that isindependent and distinct from the system that operates the firingmember.

The staple cartridge comprises a cartridge body. The cartridge bodyincludes a proximal end, a distal end, and a deck extending between theproximal end and the distal end. In use, the staple cartridge ispositioned on a first side of the tissue to be stapled and the anvil ispositioned on a second side of the tissue. The anvil is moved toward thestaple cartridge to compress and clamp the tissue against the deck.Thereafter, staples removably stored in the cartridge body can bedeployed into the tissue. The cartridge body includes staple cavitiesdefined therein wherein staples are removably stored in the staplecavities. The staple cavities are arranged in six longitudinal rows.Three rows of staple cavities are positioned on a first side of alongitudinal slot and three rows of staple cavities are positioned on asecond side of the longitudinal slot. Other arrangements of staplecavities and staples may be possible.

The staples are supported by staple drivers in the cartridge body. Thedrivers are movable between a first, or unfired position, and a second,or fired, position to eject the staples from the staple cavities. Thedrivers are retained in the cartridge body by a retainer which extendsaround the bottom of the cartridge body and includes resilient membersconfigured to grip the cartridge body and hold the retainer to thecartridge body. The drivers are movable between their unfired positionsand their fired positions by a sled. The sled is movable between aproximal position adjacent the proximal end and a distal positionadjacent the distal end. The sled comprises a plurality of rampedsurfaces configured to slide under the drivers and lift the drivers, andthe staples supported thereon, toward the anvil.

Further to the above, in these surgical end effectors, the sled is moveddistally by the firing member. The firing member is configured tocontact the sled and push the sled toward the distal end. Thelongitudinal slot defined in the cartridge body is configured to receivethe firing member. The anvil also includes a slot configured to receivethe firing member. The firing member further comprises a first cam whichengages the first jaw and a second cam which engages the second jaw. Asthe firing member is advanced distally, the first cam and the second camcan control the distance, or tissue gap, between the deck of the staplecartridge and the anvil. The firing member also comprises a knifeconfigured to incise the tissue captured intermediate the staplecartridge and the anvil. It is desirable for the knife to be positionedat least partially proximal to the ramped surfaces such that the staplesare ejected ahead of the knife.

Many surgical end effectors employ an axially movable firing beam thatis attached to the firing member and is used to apply axial firing andretraction motions to the firing member. Many of such firing beamscomprise a laminated construction that affords the firing beam with somedegree of flexure about the articulation joint. As the firing beamtraverses the articulation joint, the firing beam can applyde-articulation forces to the joint and can cause the beam to buckle. Toprevent the firing beam from buckling under pressure, the articulationjoint is commonly provided with lateral supports or “blow-out” platefeatures to support the portion of the beam that traverses thearticulation joint. To advance the firing beam through an angle ofgreater than sixty degrees, for example, a lot of axial force isrequired. This axial force must be applied to the firing member in abalanced manner to avoid the firing member from binding with the jaws asthe firing member moves distally. Any binding of the firing member withthe jaws can lead to component damage and wear as well as require anincreased amount of axial drive force to drive the firing member throughthe clamped tissue.

Other end effector designs employ a firing member that is rotarypowered. In many of such designs, a rotary drive shaft extends throughthe articulation joint and interfaces with a rotatable firing memberdrive shaft that is rotatably supported within one of the jaws. Thefiring member threadably engages the rotatable firing member drive shaftand, as the rotatable firing member drive shaft is rotated, the firingmember is driven through the end effector. Such arrangements require thesupporting jaw to be larger to accommodate the firing member driveshaft. In such devices, a lower end of the firing member commonlyoperably interfaces with the drive shaft which can also result in anapplication of forces that tend to unbalance the firing member as it isdriven distally.

FIGS. 1-4 illustrate one form of a surgical instrument 10 that mayaddress many of the challenges facing surgical instruments witharticulatable end effectors that are configured to cut and fastentissue. In various embodiments, the surgical instrument 10 may comprisea handheld device. In other embodiments, the surgical instrument 10 maycomprises an automated system sometimes referred to as arobotically-controlled system, for example. In various forms, thesurgical instrument 10 comprises a surgical end effector 1000 that isoperably coupled to an elongate shaft assembly 2000. The elongate shaftassembly 2000 may be operably attached to a housing 2002. In oneembodiment, the housing 2002 may comprise a handle that is configured tobe grasped, manipulated, and actuated by the clinician. In otherembodiments, the housing 2002 may comprise a portion of a robotic systemthat houses or otherwise operably supports at least one drive systemthat is configured to generate and apply at least one control motionwhich could be used to actuate the surgical end effectors disclosedherein and their respective equivalents. In addition, various componentsmay be “housed” or contained in the housing or various components may be“associated with” a housing. In such instances, the components may notbe contained with the housing or supported directly by the housing. Forexample, the surgical instruments disclosed herein may be employed withvarious robotic systems, instruments, components and methods disclosedin U.S. Pat. No. 9,072,535, entitled SURGICAL STAPLING INSTRUMENTS WITHROTATABLE STAPLE DEPLOYMENT ARRANGEMENTS, which is incorporated byreference herein in its entirety.

In one form, the surgical end effector 1000 comprises a first jaw 1100and a second jaw 1200. In the illustrated arrangement, the first jaw1100 comprises an elongate channel 1110 that comprises a proximal end1112 and a distal end 1114 and is configured to operably support asurgical staple cartridge 1300 therein. The surgical staple cartridge1300 comprises a cartridge body 1302 that has an elongate slot 1304therein. A plurality of surgical staples or fasteners (not shown) arestored therein on drivers (not shown) that are arranged in rows on eachside of the elongate slot 1304. The drivers are each associated withcorresponding staple cavities 1308 that open through a cartridge decksurface 1306. The surgical staple cartridge 1300 may be replaced afterthe staples/fasteners have been discharged therefrom. Other embodimentsare contemplated wherein the elongate channel 1110 and/or the entiresurgical end effector 1000 may is discarded after the surgical staplecartridge 1300 has been used. Such end effector arrangements may bereferred to as “disposable loading units”, for example.

In the illustrated arrangement, the second jaw 1200 comprises an anvil1210 that comprises an elongate anvil body 1212 that comprises aproximal end 1214 and a distal end 1216. In one arrangement, a pair ofstiffening rods or members 1213 may be supported in the anvil body 1212to provide the anvil body 1212 with added stiffness and rigidity. Theanvil body 1212 comprises a staple-forming undersurface 1218 that facesthe first jaw 1100 and may include a series of staple-forming pockets(not shown) that corresponds to each of the staples or fasteners in thesurgical staple cartridge 1300. The anvil body 1212 may further includea pair of downwardly extending tissue stop features 1220 that are formedadjacent the proximal end 1214 of the anvil body 1212. One tissue stopfeature 1220 extends from each side of the anvil body 1212 such that adistal end 1222 on each tissue stop corresponds to the proximal-moststaples/fasteners in the surgical staple cartridge 1300. When the anvil1210 is moved to a closed position onto tissue positioned between thestaple-forming undersurface 1218 of the anvil 1210 and the cartridgedeck surface 1306 of the surgical staple cartridge 1300, the tissuecontacts the distal ends 1222 of the tissue stop features 1220 toprevent the tissue from migrating proximally past the proximal-moststaples/fasteners to thereby ensure that the tissue that is cut is alsostapled. When the surgical staple cartridge is “fired” as will bediscussed in further detail below, the staples/fasteners supportedwithin each staple cavity are driven out of the staple cavity 1308through the clamped tissue and into forming contact with thestaple-forming undersurface 1218 of the anvil 1210.

As can be seen in FIGS. 5 and 6 , the proximal end 1214 of the anvilbody 1212 comprises an anvil mounting portion 1230 that includes a pairof laterally extending mounting pins 1232 that are configured to bereceived in corresponding mounting cradles or pivot cradles 1120 formedin the proximal end 1112 of the elongate channel 1110. The mounting pins1232 are pivotally retained within the mounting cradles 1120 by an anvilcap 1260 that may be attached to the proximal end 1112 of the elongatechannel 1110 by mechanical snap features 1261 that are configured toengage retention formations 1113 on the elongate channel 1110. See FIG.5 . In other arrangements, the anvil cap 1260 may be attached to theelongate channel 1110 by welding, adhesive, etc. Such arrangementfacilitates pivotal travel of the anvil 1210 relative to the surgicalstaple cartridge 1300 mounted in the elongate channel 1110 about a pivotaxis PA between an open position (FIG. 1 ) and a closed position (FIGS.2-5 ). Such pivot axis PA may be referred to herein as being “fixed” inthat the pivot axis does not translate or otherwise move as the anvil1200 is pivoted from an open position to a closed position.

In the illustrated arrangement, the elongate shaft assembly 2000 definesa shaft axis SA and comprises a proximal shaft portion 2100 that mayoperably interface with a housing of the control portion (e.g., handheldunit, robotic tool driver, etc.) of the surgical instrument 10. Theelongate shaft assembly 2000 further comprises an articulation joint2200 that is attached to the proximal shaft portion 2100 and thesurgical end effector 1000. In various instances, the proximal shaftportion 2100 comprises a hollow outer tube 2110 that may be operablycoupled to a housing 2002. See FIG. 2 . As can be seen in FIG. 6 , theproximal shaft portion 2100 may further comprise a rigid proximalsupport shaft 2120 that is supported within the hollow outer tube 2110and extends from the housing to the articulation joint 2200. Theproximal support shaft 2120 may comprise a first half 2120A and a secondhalf 2120B that may be coupled together by, for example, welding,adhesive, etc. The proximal support member 2120 comprises a proximal end2122 and a distal end 2124 and includes an axial passage 2126 thatextends therethrough from the proximal end 2122 to the distal end 2124.

As was discussed above, many surgical end effectors employ a firingmember that is pushed distally through a surgical staple cartridge by anaxially movable firing beam. The firing beam is commonly attached to thefiring member in the center region of the firing member body. Thisattachment location can introduce an unbalance to the firing member asit is advanced through the end effector. Such unbalance can lead toundesirable friction between the firing member and the end effectorjaws. The creation of this additional friction may require anapplication of a higher firing force to overcome such friction as wellas can cause undesirable wear to portions of the jaws and/or the firingmember. An application of higher firing forces to the firing beam mayresult in unwanted flexure in the firing beam as it traverses thearticulation joint. Such additional flexure may cause the articulationjoint to de-articulate—particularly when the surgical end effector isarticulated at relatively high articulation angles. The surgicalinstrument 10 employs a firing system 2300 that may address many if notall of these issues as well as others.

As can be seen in FIGS. 5-11 , in at least one embodiment, the firingsystem 2300 comprises a firing member 2310 that includes avertically-extending firing member body 2312 that comprises a top firingmember feature 2320 and a bottom firing member feature 2350. A tissuecutting blade 2314 is attached to or formed in the vertically-extendingfiring member body 2312. See FIGS. 9 and 11 . In at least onearrangement, it is desirable for the firing member 2310 to pass throughthe anvil body 1212 with low friction, high strength and high stiffness.In the illustrated arrangement, the top firing member feature 2320comprises a top tubular body 2322 that has a top axial passage 2324extending therethrough. See FIG. 10 . The bottom firing member feature2350 comprises a bottom tubular body 2352 that has a bottom axialpassage 2354 extending therethrough. In at least one arrangement, thetop firing member feature 2320 and the bottom firing member feature 2350are integrally formed with the vertically-extending firing member body2312. As can be seen in FIG. 12 , the anvil body 1212 comprises anaxially extending anvil slot 1240 that has a cross-sectional shape thatresembles a “keyhole”. Similarly, the elongate channel 1110 comprises anaxially extending channel slot 1140 that also has a keyholecross-sectional shape.

Traditional firing member arrangements employ long flexible cantileverwings that extend from a top portion and a bottom portion of the firingmember. These cantilever wings slidably pass through slots in the anviland channel that are commonly cut with a rectangular t-cutter whichtended to produce higher friction surfaces. Such long cantilever wingshave minimum surface area contact with the anvil and channel and canresult in galling of those components. The keyhole-shaped channel slot1140 and keyhole-shaped anvil slot 1240 may be cut with a round t-cutterand may be finished with a reamer/borer which will result in thecreation of a lower friction surface. In addition, the top tubular body2322 and the bottom tubular body 2352 tend to be stiffer than the priorcantilever wing arrangements and have increased surface area contactwith the anvil and channel, respectively which can reduce galling andlead to a stronger sliding connection. Stated another way, because theanvil slot 1240 and the channel slot 1140 are keyhole-shaped and haveless material removed than a traditional rectangular slot, the geometryand increased material may result in a stiffer anvil and channel whencompared to prior arrangements.

Turning to FIGS. 9-11 , in one arrangement, the firing system 2300further comprises an upper flexible spine assembly 2400 that is operablycoupled to the top firing member feature 2320 and a lower flexible spineassembly 2500 that is operably coupled to the bottom firing memberfeature 2350. In at least one embodiment, the upper flexible spineassembly 2400 comprises an upper series 2410 of upper vertebra members2420 that are loosely coupled together by an upper flexible couplermember 2402 that is attached to the top firing member feature 2320. Theupper flexible coupler member 2402 may comprises a top cable 2404 thatextends through the top axial passage 2324 in the top firing memberfeature 2320 and a distal end 2406 of the top cable 2404 is attached toa retainer ferrule 2408 that is secured with the top axial passage 2324.

As can be seen in FIG. 13 , each upper vertebra member 2420 comprises anupper vertebra body portion 2422 that has a proximal end 2424 and adistal end 2428. An upper hollow passage 2429 extends through the uppervertebra body portion 2422 to accommodate passage of the upper flexiblecoupler member 2402 therethrough. Each upper vertebra member 2420further comprises a downwardly extending upper drive feature or uppervertebra member tooth 2450 that protrudes from the upper vertebra bodyportion 2422. Each upper vertebra member tooth 2450 has a helix-shapedproximal upper face portion 2452 and a helix-shaped distal upper faceportion 2454. Each proximal end 2424 of the upper vertebra body portions2422 has an upper proximal mating feature 2426 therein and each distalend 2428 has an upper distal mating feature 2430 formed therein. In atleast one embodiment, the upper proximal mating feature 2426 comprises aconcave recess 2427 and each upper distal mating feature 2430 comprisesa convex mound 2431. When arranged in the upper series 2410, the convexmound 2431 on one upper vertebra member 2420 contacts and mates with theconcave recess 2427 on an adjacent upper vertebra member 2420 in theupper series 2410 to maintain the upper vertebra members 2420 roughly inalignment so that the helix-shaped proximal upper face portion 2452 anda helix-shaped distal upper face portion 2454 on each respective uppertooth 2450 can be drivingly engaged by a rotary drive screw 2700 as willbe discussed in further detail below.

Similarly, in at least one embodiment, the lower flexible spine assembly2500 comprises a lower series 2510 of lower vertebra members 2520 thatare loosely coupled together by a lower flexible coupler member 2502that is attached to the bottom firing member feature 2350. The lowerflexible coupler member 2502 may comprises a lower cable 2504 thatextends through the bottom axial passage 2354 in the bottom firingmember feature 2350 and a distal end 2506 of the bottom cable 2504 isattached to a retainer ferrule 2508 that is secured with the bottomaxial passage 2354.

As can be seen in FIG. 14 , each lower vertebra member 2520 comprises alower vertebra body portion 2522 that has a proximal end 2524 and adistal end 2528. A lower hollow passage 2529 extends through the lowervertebra body portion 2522 to accommodate passage of the lower flexiblecoupler member 2502 therethrough. Each lower vertebra member 2520further comprises an upwardly extending lower drive feature or lowervertebra member tooth 2550 that protrudes upward from the lower vertebrabody portion 2522. Each lower vertebra member tooth 2550 has ahelix-shaped proximal lower face portion 2552 and a helix-shaped distallower face portion 2554. Each proximal end 2524 of the lower vertebrabody portions 2522 has a lower proximal mating feature 2526 therein andeach distal end 2528 has a lower distal mating feature 2530 formedtherein. In at least one embodiment, the lower proximal mating feature2526 comprises a concave recess 2527 and each lower distal matingfeature 2530 comprises a convex mound 2531. When arranged in the lowerseries 2510, the convex mound 2531 on one lower vertebra member 2520contacts and mates with the concave recess 2527 on an adjacent lowervertebra member 2520 in the lower series 2510 to maintain the lowervertebra members 2520 roughly in alignment so that the helix-shapedproximal lower face portion 2552 and a helix-shaped distal lower faceportion 2554 on each respective lower vertebra member tooth 2550 can bedrivingly engaged by a rotary drive screw 2700 as will be discussed infurther detail below.

Now turning to FIGS. 5, 7, and 8 , in at least one arrangement, thefiring drive system 2300 further comprises a rotary drive screw 2700that is configured to drivingly interface with the upper series 2410 ofupper vertebra members 2420 and the lower series 2510 of lower vertebramembers 2520. In the illustrated arrangement, the rotary drive screw2700 is driven by a rotary drive system 2600 that comprises a proximalrotary drive shaft 2610 that is rotatably supported within the axialpassage 2126 within the proximal support shaft 2120. See FIG. 7 . Theproximal rotary drive shaft 2610 comprises a proximal end 2612 and adistal end 2614. The proximal end 2612 may interface with a gear box2004 or other arrangement that is driven by a motor 2006 or other sourceof rotary motion housed in the housing of the surgical instrument. SeeFIG. 2 . Such source of rotary motion causes the proximal rotary driveshaft to rotate about the shaft axis SA within the axial passage 2126 inthe proximal support shaft 2120.

The proximal rotary drive shaft 2610 is operably supported within theelongate shaft assembly 2000 in a location that is proximal to thearticulation joint 2200 and operably interfaces with a constant velocity(CV) drive shaft assembly 2620 that “spans” or extends axially throughthe articulation joint 2200. As can be seen in FIGS. 8, 16, and 17 , inat least one arrangement, the CV drive shaft assembly 2620 comprises aproximal CV drive assembly 2630 and a distal CV drive shaft 2670. Theproximal CV drive assembly 2630 comprises a proximal shaft segment 2632that consists of an attachment shaft 2634 that is configured to benon-rotatably received within a similarly-shaped coupler cavity 2616 inthe distal end 2614 of the proximal rotary drive shaft 2610. Theproximal shaft segment 2632 operably interfaces with a series 2640 ofmovably coupled drive joints 2650.

As can be seen in FIG. 18 , in at least one arrangement, each drivejoint 2650 comprises a first or distal sphere portion 2660 and a secondor proximal sphere portion 2652. The distal sphere portion 2660 islarger than the proximal sphere portion 2652. The distal sphere portion2660 comprises a socket cavity 2662 that is configured to rotatablyreceive a proximal sphere portion 2652 of an adjacent drive joint 2650therein. Each proximal sphere portion 2652 comprises a pair ofdiametrically opposed joint pins 2654 that are configured to be movablyreceived in corresponding pin slots 2664 in the distal sphere portion2660 of an adjacent drive joint 2650 as can be seen in FIG. 16 . Aproximal sphere portion 2652P of a proximal-most drive joint 2650P isrotatably received in a distal socket portion 2636 of the proximal shaftsegment 2632 as shown in FIG. 16 . The joint pins 2654P are receivedwithin corresponding pin slots 2637 in the distal socket portion 2636.As can be further seen in FIG. 16 , a distal-most drive joint 2650D inthe series 2640 of movably coupled drive joints 2650 is movably coupledto a distal CV drive shaft 2670.

In at least one arrangement, the distal CV drive shaft 2670 comprises aproximal sphere portion 2672 that is sized to be movably received in thesocket cavity 2662D in the distal-most drive joint 2650D. The proximalsphere portion 2672 includes joint pins 2674 that are movably receivedin the pin slots 2664D in the distal-most drive joint 2650D. The distalCV drive shaft 2670 further comprises a distally extending shaft stem2676 that is configured to be non-rotatably coupled to the rotary drivescrew 2700 that is positioned distal to the articulation joint 2200. Thedistal CV drive shaft 2670 includes a flange 2677 and a mounting barrelportion 2678 for receiving a thrust bearing housing 2680 thereon.

In the illustrated arrangement, when the series 2640 of movably coupleddrive joints 2650 articulates, the joint pins 2674 remain in thecorresponding pin slots 2664 of an adjacent drive joint 2650. In theexample illustrated in FIG. 18 , each drive joint may be capable ofapproximately eighteen degrees of articulation in the pitch and yawdirections. FIG. 16 illustrates an angle of the series of 2640 of drivejoints 2650 when each drive joint 2650 in the series are fullyarticulated ninety degrees in pitch and yaw which yields an angle α ofapproximately 100.9 degrees. In such arrangement, the outer surface ofeach distal sphere portion 2660 clears the outer surface of the adjacentor adjoining proximal sphere portion 2652 allowing for unrestrictedmotion until the eighteen degree limit is reached. The rigid design andlimited small angles allow the series 2640 of movably coupled drivejoints 2650 to carry high loads torsionally at an overall large angle.

In the illustrated arrangement, the articulation joint 2200 comprises anarticulation joint spring 2230 that is supported within an outerelastomeric joint assembly 2210. The outer elastomeric joint assembly2210 comprises a distal end 2212 that is attached to the proximal end1112 of the elongate channel 1110. For example, as can be seen in FIG. 6, the distal end 2212 of the outer elastomeric joint assembly 2210 isattached to the proximal end 1112 of the elongate channel 1110 by a pairof cap screws 2722 that extend through a distal mounting bushing 2720 tobe threadably received in the proximal end 1112 of the elongate channel1110. A proximal end 2214 of the elastomeric joint assembly 2210 isattached to the distal end 2124 of the proximal support shaft 2120. Theproximal end 2214 of the elastomeric joint assembly 2210 is attached tothe distal end 2124 of the proximal support member 2120 by a pair of capscrews 2732 that extend through a proximal mounting bushing 2750 to bethreadably received in threaded inserts 2125 mounted within the distalend 2124 of the proximal support shaft 2120.

To prevent the drive joints 2650 from buckling during articulation, theseries 2640 of movably coupled drive joints 2650 extend through at leastone low friction articulation joint spring 2730 that is supported withinthe outer elastomeric joint assembly 2210. See FIG. 19 . Thearticulation joint spring 2730 is sized relative to the drive joints2650 such that a slight radial clearance is provided between thearticulation joint spring 2730 and the drive joints 2650. Thearticulation joint spring 2730 is designed to carry articulation loadsaxially which may be significantly lower than the torsional firingloads. The joint spring(s) is longer than the series 2640 of drivejoints 2650 such that the drive joints are axially loose. If the “hardstack” of the series 2640 of drive joints 2650 is longer than thearticulation joint spring(s) 2730 hard stack, then the drive joints 2650may serve as an articulation compression limiter causing firing loadsand articulation loads to resolve axially through the series 2640 of thedrive joints 2650. When the firing loads resolve axially through theseries 2640 of the drive joints 2650, the loads may try to straightenthe articulation joint 2200 or in other words cause de-articulation. Ifthe hard stack of the articulation joint spring(s) 2730 is longer thanthe hard stack of the series 2640 of the drive joints 2650, the firingloads will then be contained within the end effector and no firing loadswill resolve through the drive joints 2650 or through the springs(s)2730.

To further ensure that the drive joints 2650 are always engaged witheach other, a proximal drive spring 2740 is employed to apply an axialbiasing force to the series 2640 of drive joints 2650. For example, ascan be seen in FIGS. 8, 19, and 20 , the proximal drive spring 2740 ispositioned between the proximal mounting bushing 2734 and a supportflange that is formed between the distal socket portion 2636 and aproximal barrel portion 2638 of the proximal shaft segment 2632. In onearrangement, the proximal drive spring 2740 may comprise an elastomericO-ring/bushing received on the proximal barrel portion 2638 of theproximal shaft segment 2632. The proximal drive spring 2740 lightlybiases the drive joints 2650 together to decrease any gaps that mayoccur during articulation. This ensures that the drive joints 2650transfer loads torsionally. It will be appreciated, however, that in atleast one arrangement, the proximal drive spring 2740 does not apply ahigh enough axial load to cause firing loads to translate through thearticulation joint 2200.

As can be seen in FIGS. 9 and 10 , the top firing member feature 2320 onthe firing member 2310 comprises a distal upper firing member toothsegment 2330 that is equivalent to one half of an upper tooth 2450 oneach upper vertebra member 2420. In addition, a proximal upper firingmember tooth 2336 that is identical to an upper tooth 2450 on each uppervertebra member 2420 is spaced from the distal upper firing member toothsegment 2330. The distal upper firing member tooth segment 2330 and theproximal upper firing member tooth 2336 may be integrally formed withthe top firing member feature 2320 of the firing member 2310. Likewise,the bottom firing member feature 2350 of the firing member 2310comprises a distal lower firing member tooth 2360 and a proximal lowerfiring member tooth 2366 that are integrally formed on the bottom firingmember feature 2350. For example, in at least one arrangement, thefiring member 2310 with the rigidly attached teeth 2330, 2336, 2360, and2366 may be fabricated at one time as one unitary component usingconventional metal injection molding techniques.

As indicated above, each of the upper vertebra members 2520 is movablyreceived on an upper flexible coupler member 2402 in the form of a topcable 2404. As was described above, the distal end 2406 of the top cable2404 is secured to the top firing member feature 2320 of the firingmember 2310. Similarly, each of the lower vertebra members 2520 ismovably received on a lower flexible coupler member 2502 in the form ofa lower cable 2504. A distal end 2506 of the lower cable 2504 is securedto the bottom firing member feature 2350 of the firing member 2310. Inat least one arrangement, the top cable 2404 and the bottom cable 2504extend through the proximal shaft portion 2100 and, as will be discussedin further detail below, may interface with a bailout arrangementsupported in the housing for retracting the firing member 2310 back toits home or starting position should the firing member drive systemfail.

Turning again to FIG. 8 , the axial length AL_(u) of the upper series2410 of upper vertebra members 2420 and the axial length AL_(l) of thelower series 2510 of lower vertebra members 2520 are equal and must besufficiently long enough to facilitate the complete distal advancementof the firing member 2310 from the home or starting position to adistal-most ending position within the staple cartridge while theproximal-most upper vertebra members 2420 in the upper series 2410 ofupper vertebra members 2420 and the proximal-most lower vertebra members2520 in the lower series 2510 of lower vertebra members 2520 remain indriving engagement with the rotary drive screw 2700. As can be seen inFIG. 8 , an upper compression limiting spring 2421 is configured tointerface with a proximal-most upper vertebra member 2420P in the upperseries 2410 of upper vertebra members 2420. The upper compressionlimiting spring 2421 is journaled on the top cable 2404 and is retainedin biasing engagement with the proximal-most upper vertebra member 2420Pby an upper spring holder 2423 that is retained in position by an upperferrule 2425 that is crimped onto the top cable 2404. The top cable 2404extends through an upper hypotube 2433 that is supported in the proximalsupport shaft. Likewise, a lower compression limiting spring 2521 isconfigured to interface with a proximal-most, lower vertebra member2520P in the lower series 2510 of lower vertebra members 2520. The lowercompression spring 2521 is journaled on the lower cable 2504 and isretained in biasing engagement with the proximal-most, lower vertebramember 2520P by a lower spring holder 2523 that is retained in positionby a lower ferrule 2525 that is crimped onto the lower cable 2504. Thelower cable 2504 extends through a lower hypotube 2533 that is supportedin the proximal support shaft.

When the upper vertebra members 2420 and the lower vertebra members 2520angle through the articulation joint (after the end effector has beenpositioned in an articulated position), the gaps between the respectivevertebra members 2420, 2520 increase in each series 2410, 2510 whichcauses the springs 2421, 2521 to become tighter. The compressionlimiting springs 2421, 2521 provide enough slack in the cables 2404,2504, respectively to enable the vertebra members 2420, 2520 anglethrough the most extreme articulation angles. If the cables 2404, 2504are pulled too tight, the spring holders 2423, 2523 will contact theirrespective proximal-most vertebra members 2420P, 2520P. Such compressionlimiting arrangements ensure that the vertebra members 2420, 2520 intheir respective series 2410, 2510 always remain close enough togetherso that the rotary drive screw 2700 will always drivingly engage them inthe manner discussed in further detail below. When the vertebra members2420, 2520 are aligned straight again, the compression limiting springs2421, 2521 may partially relax while still maintaining some compressionbetween the vertebra members.

As indicated above, when the upper vertebra members 2420 are arranged inthe upper series 2410 and lower vertebra members 2520 are arranged inthe lower series 2510, the convex mounds and concave recesses in eachvertebra member as well as the compression limiter springs serve tomaintain the upper and lower vertebra members in relatively linearalignment for driving engagement by the rotary drive screw 2700. As canbe seen in FIGS. 9 and 10 , when the upper vertebra members 2420 are inlinear alignment, the upper teeth 2450 are spaced from each other by anopening space generally designated as 2460 that facilitates drivingengagement with the helical drive thread 2170 on the rotary drive screw.Similarly, when the lower vertebra members 2520 are in linear alignment,the lower vertebra member teeth 2550 are spaced from each other by anopening space generally designated as 2560 that facilitates drivingengagement with the helical drive thread 2170 of the rotary drive screw2700.

Turning to FIGS. 8 and 22 , the rotary drive screw 2700 comprises ascrew body 2702 that has a socket 2704 therein for receiving thedistally extending shaft stem 2676 of the distal CV drive shaft 2670. Aninternal radial groove 2714 (FIG. 10 ) is formed in the screw body 2702for supporting a plurality of ball bearings 2716 therein. In onearrangement, for example, 12 ball bearings 2716 are employed. The radialgroove 2714 supports the ball bearings 2716 between the screw body 2702and a distal end of the thrust bearing housing 2680. The ball bearings2716 serve to distribute the axial load of the rotary drive screw 2700and significantly reduce friction through the balls' rolling motion.

As can be seen in FIG. 23 , a helical drive thread 2710 is providedaround the screw body 2702 and serves to form a proximal thread scoopfeature 2712. The proximal thread scoop feature 2712 is formed with afirst pitch 2713 and the remaining portion of the helical drive thread2710 is formed with a second pitch 2715 that differs from the firstpitch 2713. In FIGS. 22 and 23 , area 2718 illustrates where the firstpitch 2713 and the second pitch 2715 converge. In at least oneembodiment, the first pitch 2713 is larger than the second pitch 2715 toensure that the rotary drive screw 2700 captures and “scoops up” ordrivingly engages every upper vertebra member 2420 and every lowervertebra member 2520. As can be seen in FIG. 24 , a proximal end 2717 ofthe helical drive thread 2710 that has the first pitch 2713 has scoopedinto the into the opening space 2560 between two adjacent lower vertebramember teeth 2550A and 2550B while the center portion 2719 of thehelical drive thread 2710 that has the second pitch 2715 is in drivingengagement with the helix-shaped distal lower face portion 2554 on thelower vertebra member tooth 2550B and the helix-shaped proximal lowerface portion 2552 on the proximal lower firing member tooth 2366. As canalso be appreciated, the scoop feature 2712 may not contact thehelix-shaped distal lower face portion 2554A of the lower vertebramember tooth 2550A as it scoops up the lower vertebra member tooth 2550Bwhen driving the firing member 2310 distally. The helical drive thread2710 interacts with the teeth 2450 of the upper vertebra members 2420 ina similar manner.

A power screw is a threaded rod with a full three hundred sixty degreenut around it. Rotation of the power screw causes the nut to advance ormove longitudinally. In the present arrangements, however, due to spaceconstraints, a full three hundred sixty degree nut cannot fit inside theend effector. In a general sense, the upper flexible spine assembly 2400and the lower flexible spine assembly 2500 comprise aradially/longitudinally segmented “power screw nut” that is rotatablydriven by the rotary drive screw 2700. When the rotary drive screw isrotated in a first rotary direction, the rotary drive screw 2700 drivesone or more vertebra members in each of the upper series and lowerseries of vertebra members longitudinally while the vertebra members2420, 2520 stay in the same locations radially. The upper series 2410and lower series 2510 are constrained from rotating around the rotarydrive screw 2700 and can only move longitudinally. In one arrangement,the upper vertebra members 2420 in the upper series 2410 and the lowervertebra members 2520 in the lower series 2510 only surround the rotarydrive screw 2700 with less than ten degrees each.

FIG. 25 illustrates the firing member 2310 in the home or startingposition. As can be seen in FIG. 25 , a portion of the helical drivethread 2710 on the rotary drive screw 2700 is engaged between the distalupper firing member tooth segment 2330 and the proximal upper firingmember tooth 2336 and another portion of the helical drive thread 2710is engaged between the distal lower firing member tooth 2360 and aproximal lower firing member tooth 2366 on the firing member 2310. Sucharrangement enables the rotary drive screw 2700 to precisely control thedistal and proximal movement of the firing member 2310 which, as will bediscussed in further detail below, can result in the precise movement ofthe anvil 1210. Once the firing member 2310 has been sufficientlydistally advanced during a firing stroke, the helical drive thread 2710operably engages the teeth on the upper and lower vertebras. See FIG. 26.

The surgical instrument 10 also comprises an articulation system 2240that is configured to apply articulation motions to the surgical endeffector 1000 to articulate the surgical end effector relative to theelongate shaft assembly 2000. In at least one arrangement, for example,the articulation system comprises four articulation cables 2242, 2246,2250, and 2254 that extend through the elongate shaft assembly 2000. SeeFIG. 27 . In the illustrated arrangement, the articulation cables 2242,2246 pass through the proximal mounting bushing 2750, the proximal end2214 of the elastomeric joint assembly 2210, as well as a central ribsegment 2216 to be secured to the distal end 2212 of the elastomericjoint assembly 2210 or other portion of the surgical instrument.Likewise, the articulation cables 2250 and 2254 extend through theproximal mounting bushing 2750, the proximal end 2214 of the elastomericjoint assembly 2210, as well as a central rib segment 2218 to be securedto the distal end 2212 of the elastomeric joint assembly 2210 or otherportion of the surgical end effector. The cables 2242, 2246, 2250, and2254 operably interface with an articulation control system that issupported in the housing of the surgical instrument 10. For example, aproximal portion of each cable 2242, 2246, 2250, and 2254 may be spooledon a corresponding rotary spool or cable-management system 2007 (FIG. 2) in the housing portion of the surgical instrument 10 that isconfigured to payout and retract each cable 2242, 2246, 2250, and 2254in desired manners. The spools/cable management system may be motorpowered or manually powered (ratchet arrangement, etc.). FIG. 29illustrates articulation of the surgical end effector 1000 through afirst articulation plane relative to the elongate shaft assembly 2000.FIG. 30 illustrates articulation of the surgical end effector 1000through a second articulation plane relative to the elongate shaftassembly 2000. FIG. 31 illustrates articulation of the surgical endeffector 1000 through multiple articulation planes relative to theelongate shaft assembly 2000.

FIGS. 32-34 illustrate an alternative articulation joint 2200′ in theform of an elastomeric joint assembly 2210′. As can be seen in FIG. 33 ,each articulation cable passes through a corresponding spring 2215′ thatis mounted in the ribs 2216′ of the elastomeric joint assembly 2210′.For example, cable 2242 extends through spring 2244. Cable 2246 extendsthrough spring 2248. Cable 2250 extends through spring 2252 and cable2254 extends through spring 2256. As indicated above, the end effectoris articulated by pulling on and relaxing the appropriate cables 2242,2246, 2250 and 2254. To achieve higher articulation angles with greaterjoint stability, each of the springs 2244, 2248, 2252, and 2256 canslide through the ribs of the elastomeric joint to push the end effectorand pull on the cables extending therethrough. The springs 2244, 2248,2252, and 2256 will also retract into the ribs when the cables 2242,2246, 2250, and 2254 are pulled tight. Each of the springs 2244, 2248,2252, and 2256 loosely seat over the particular cable that passestherethrough. Each cable and corresponding spring may terminate orotherwise be coupled to a corresponding solid rod that is supported inthe elongate shaft assembly 2000 and may be pushed and pulled from itsproximal end. When the cable is pulled, the corresponding spring wouldcarry little to no load. When the spring is pushed, the cable wouldcarry little load, but will help limit the end effector movement. Thisinteraction between the cable and spring may facilitate higherarticulation angles that may approach ninety degrees, for example.

Because the radially/longitudinally segmented power screw nutarrangement disclosed herein does not have the same constraints as athree hundred sixty degree nut, the upper vertebra members 2420 in theupper series 2410 and the lower vertebra members 2520 in the lowerseries 2510 are constrained to ensure that their loads are transferredto the firing member in a longitudinal direction. To maintain each ofthe upper vertebra members 2420 in the desired orientation and toprevent the upper vertebra members 2420 from becoming snagged ordisoriented when traversing through the articulation joint 2200, theupper vertebra members 2420 are aligned to pass through an upper sleeve2470 that extends through an upper portion of the outer elastomericjoint assembly 2210 of the articulation joint 2200. See FIGS. 27, 28,and 35 . A distal end 2472 of the upper sleeve 2470 is supported in theproximal end 1112 of the elongate channel 1110 and a proximal end 2474of the upper sleeve 2470 is supported in the distal end of the proximalsupport shaft 2120. The upper sleeve 2470 is fabricated from a polymeror plastic material that has a low coefficient of friction and isflexible to enable the upper sleeve 2470 to flex with the outerelastomeric joint assembly 2210. The upper sleeve 2470 protects theupper vertebra members 2420 from contacting the outer elastomeric jointassembly 2210 that is fabricated from an elastomeric material that mayhave a higher coefficient of friction than the coefficient of frictionof the material of the upper sleeve 2470. Stated another way, the uppersleeve 2470 forms a low friction, flexible, continuous, uninterrupted,and fully encapsulating path for the upper vertebra members 2420 as theytraverse the articulation joint 2200.

Similarly, a lower sleeve 2570 is employed to support the lower vertebramembers 2520 as they pass through the articulation joint 2200. A distalend 2572 of the lower sleeve 2570 is supported in the proximal end ofthe elongate channel and a proximal end of the lower sleeve 2570 issupported in the distal end of the proximal support shaft 2120. Like theupper sleeve 2470, the lower sleeve 2570 is fabricated from a polymer orplastic material that has a low coefficient of friction and is flexibleto enable the lower sleeve 2570 to flex with the outer elastomeric jointassembly 2210. The lower sleeve 2570 protects the lower vertebra members2520 from contacting the outer elastomeric joint assembly 2210 as theypass through the articulation joint 2200. Stated another way, the lowersleeve 2570 forms a low friction, flexible, continuous, uninterrupted,and fully encapsulating path for the lower vertebra members 2520 as theytraverse the articulation joint 2200. In various embodiments, the uppersleeve 2470 and the lower sleeve 2570 are configured to bend freelywithout creating a kink. To prevent the formation of kinks in thesleeves, in at least one arrangement, the sleeves 2470, 2570 aresupported within the outer elastomeric joint assembly 2210 such that thesleeves may move axially. For example, when the articulation jointangles up, the lower sleeve 2570 may slide distally and have a largebend radius; the upper sleeve 2470 in the same example, may slideproximally and have a tighter bend radius. By moving axially, the amountof material exposed outside of the joint assembly 2210 which mightotherwise be susceptible to kinking under a tight bend radius isreduced. In at least one arrangement, the distal end 2472 of the uppersleeve 2470 is formed with an upper scoop 2476 that is configured tofunnel the upper vertebra members 2420 into the anvil cap 1260.Similarly, the distal end of the lower sleeve 2570 may be formed with alower scoop that is configured to funnel the lower vertebra members 2520into the channel slot 1140 in the elongate channel 1110.

As indicated above, the anvil mounting portion 1230 comprises a pair oflaterally extending mounting pins 1232 that are configured to bereceived in corresponding mounting cradles or pivot cradles 1120 thatare formed in the proximal end 1112 of the elongate channel 1110. Themounting pins 1232 are pivotally retained within the mounting cradles1120 by an anvil cap 1260 that is attached to the proximal end 1112 ofthe elongate channel 1110 in the above-described manners. The anvil cap1260 comprises a proximal end 1262 and a distal end 1264 and has akeyhole-shaped vertebra passage 1266 extending therethrough toaccommodate passage of the top firing member feature 2320 and uppervertebra members 2420 therethrough. FIG. 36 illustrates the vertebrapassage 1266 in the anvil cap 1260. When the rotary drive screw 2700applies load to the upper vertebra members 2420, the vertebra members2420 will tend to tilt about the area A in FIG. 37 , so the uppervertebra member tooth 2450 is no longer square with the rotary drivescrew 2700 and may instead experience a higher-pressure line contact.Areas B in FIG. 37 show where the upper vertebra member 2420 stopstilting. To ensure that most of the loads stay in the longitudinaldirection to perform useful work, the upper vertebra member tooth 2450must be angled the same amount as the upper vertebra member 2420 tilts.Thus, when the upper vertebra member 2420 tilts, the upper vertebramember tooth 2450 will still maintain surface contact with the helicaldrive member 2710 on the rotary drive screw 2700 and all loads will bedirected longitudinally and not vertically. The slightly angled uppervertebra member tooth 2450 may behave like a square thread when thevertebra member 2420 is tilted and better distributes loads to lower thepressure contact. By directing most of the loads in the longitudinaldirection, vertical loads are avoided which could result in theestablishment of friction that would counter the longitudinal loads. Theupper vertebra members 2420 react similarly as they pass down thekeyhole-shaped anvil slot 1240. Likewise, the lower vertebra members2520 react similarly as they pass through the keyhole-shaped axiallyextending channel slot 1140 in the elongate channel 1110.

In the illustrated arrangement, the anvil 1210 is moved to the openposition by a pair of anvil springs 1270 that are supported within theproximal end of the elongate channel. See FIGS. 38, 42, and 43 . Thesprings 1270 are positioned to apply a pivotal biasing force tocorresponding anvil control arms 1234 that may be integrally formed withanvil mounting portion 1230 and extend downwardly therefrom. See FIG. 38.

FIGS. 39-41 illustrate portions of the anvil 1210, the firing member2310, and the anvil cap 1260 when the anvil 1210 is open (FIG. 39 ),when the anvil 1210 is partially closed (FIG. 40 ) and after the firingmember has been advanced distally from the home or starting position(FIG. 41 ). As can be seen in FIG. 39 , when the firing member 2310 isin the home or starting position, the top firing member feature 2320 iscompletely received within the vertebra passage 1266 in the anvil cap1260. During a firing stroke, the top firing member feature 2320 and theupper vertebra members 2420 in the upper series 2410 must transitionfrom the vertebra passage 1266 in the anvil cap 1260 to thekeyhole-shaped anvil slot 1240. Thus, it is desirable to minimize anygap “G” between the anvil mounting portion 1230 and a distal end 1264 ofthe anvil cap 1260. To minimize this gap G while facilitate unimpededpivotal travel of the anvil 1210, the distal end 1264 of the anvil cap1260 is formed with a curved cap surface 1265 that matches a curvedmating surface 1231 on the anvil mounting portion 1230. Both surfaces1265, 1231 are curved and concentric about the pivot axis PA or someother point. Such arrangement allows the anvil 1210 to move radially andnot interfere with the anvil cap 1260 while maintaining a minimal gap Gtherebetween. The gap G between the anvil mounting portion 1230 and thedistal end 1264 of the anvil cap 1260 is significantly shorter than alength of an upper vertebra member 2420 which facilitates easytransition of each upper vertebra member 2420 from the vertebra passage1266 in the anvil cap 1260 to the keyhole-shaped anvil slot 1240. Inaddition, to further assist with the transition of the top firing memberfeature 2320 into the keyhole-shaped anvil slot 1240, a ramped surface1241 is formed adjacent the curved mating surface 1231 on the anvilmounting portion 1230. As the firing member 2310 is initially advanceddistally from the home or starting position, a distal end of the topfiring member feature 2320 contacts the ramped surface 1241 and beginsto apply a closing motion to the anvil 1210 as can be seen in FIG. 40 .Further distal advancement of the firing member 2310 during the firingstroke or firing sequence causes the top firing member feature to enterthe keyhole shaped anvil slot 1240 to completely close the anvil 1210and retain the anvil 1210 in the closed position during the firingsequence. See FIG. 41 .

In general, the highest firing forces established in an endocutter areassociated with cutting and stapling tissue. If those same forces can beused to close the anvil, then the forces generated during pre-clampingand grasping of tissue can be high as well. In at least one arrangement,the firing member body 2312 further comprises a firing member wing ortab 2355 that extends laterally from each lateral side of the firingmember body 2312. See FIGS. 15 and 36 . The firing member wings 2355 arepositioned to contact the corresponding anvil control arms 1234 when thefiring member 2310 is driven in the proximal direction PD from the homeor starting position to quickly close the anvil 1210 for graspingpurposes. In at least one arrangement, when the firing member 2310 is inthe home or starting position, the firing member wings 2355 are locateddistal to the anvil control arms 1234 as shown in FIG. 42 . When thefiring member 3210 is moved proximally, the firing member wings 2355push the anvil control arms 1234 (pivotal direction C) against the biasof the anvil springs 1270. See FIG. 42 . In one arrangement, the firingmember 2310 only has to move a short distance D to pivot the anvil 1210to a closed position. In one embodiment, distance D may be approximately0.070 inches long, for example. This short movement allows for a quickresponse. Because the anvil pivot point or pivot axis PA is relativelyfar from the firing member wings 2355 which creates a substantial momentarm, the proximal movement of the firing member 2310 (and firing memberwings 2355) results in an application of high pre-compression torque tothe anvil 1210 to move the anvil 1210 to a closed position. Thus, thefiring member wings 2355 may be referred to herein as “pre-compressionfeatures”. See FIG. 43 . Thus, the clinician may use the surgical endeffector 1000 to grasp and manipulate tissue between the anvil 1210 andthe surgical staple cartridge 1300 without cutting the tissue andforming the staples, by advancing the firing member 2310 proximally theshort distance D to cause the anvil 1210 to quickly pivot to a closedposition.

The firing member 2310 may be moved in the proximal direction PD byrotating the rotary drive screw 2700 in a second rotary direction. Thus,when the firing member 2310 is in the “home” or starting position, theanvil 1210 may be biased into the fully open position by the anvilsprings 1270. Activation of the rotary drive system 2600 to apply arotary motion to the rotary drive screw 2700 in a first rotary directionwill cause the firing member 2310 to be advanced distally from the homeor starting position to apply an anvil closure motion to the anvil 1210to move the anvil closed to clamp the target tissue between the anvil1210 and the surgical staple cartridge 1300. Continued rotation of therotary drive screw in the first rotary direction will cause the firingmember 2310 to continue to distally advance through the surgical endeffector 1000. As the firing member 2310 moves distally, the firingmember 2310 contacts a sled 1312 (FIG. 19 ) that is supported in thesurgical staple cartridge 1300 and drives the sled 1312 distally throughthe staple cartridge body 1302. When the firing member 2310 is in thehome or starting position, the surgeon may wish to use the surgical endeffector to grasp and manipulate tissue. To do so, the rotary drivesystem is actuated to apply a second rotary drive motion to the rotarydrive screw 2700 in a second rotary direction that is opposite to thefirst rotary direction. Such rotary movement of the rotary drive screw2700 in the second rotary direction will drive the firing member 2310proximally from the starting position and cause the anvil 1210 toquickly pivot to the closed position. Thus, in accordance with at leastone embodiment, the “home or starting position” of the firing member2310 is not its proximal-most position.

If during the firing process, the rotary drive system 2600 quitsrotating, the firing member 2310 may become stuck within the surgicalend effector. In such instance, the top firing member feature 2320 mayremain engaged with the anvil 1210 and the bottom firing member feature2350 may remain engaged with the elongate channel 1110 and therebyprevent the surgeon from moving the anvil 1210 to an open position torelease the tissue clamped between anvil 1210 and surgical staplecartridge 1300. This could occur, for example, if the motor or othercontrol arrangement supplying the rotary drive motions to the rotarydrive shaft 2610 fails or otherwise becomes inoperative. In suchinstances, the firing member 2310 may be retracted back to the home orstarting position within the surgical end effector 1000 by pulling thetop cable 2404 and the lower cable 2504 in a proximal direction. Forexample, a proximal portion of the top cable 2404 and a proximal portionof the lower cable 2505 may be spooled on a rotary spool orcable-management system 2009 (FIG. 2 ) in the housing portion of thesurgical instrument 10 that is configured to payout the top cable 2404and lower cable 2504 during the firing stroke and also retract thecables 2404, 2504 in a proximal direction should the firing member 2310need to be retracted. The cable management system 2009 may be motorpowered or manually powered (ratchet arrangement, etc.) to applyretraction motions to the cables 2404, 2504. When the cables 2404, 2504are retracted, the upper vertebra members 2420 and lower vertebramembers 2520 will cause the rotary drive screw 2700 to spin in reverse.

The following equation may be used to determine whether the rotary drivescrew 2700 will spin in reverse depending upon the lead (L), pitchdiameter (d_(p)), tooth angle (α) and friction (μ):

$\mu \geq {\frac{L}{\pi d_{p}}\cos\alpha}$

The rotary drive screw 2700 may self-lock if the above equation is true.For the most part, in many instances, the pitch diameter is mostly fixedfor an endocutter, but the lead and tooth angle are variable. Becausethe upper vertebra member teeth 2450 and lower vertebra member teeth2550 are mostly square, the rotary drive screw 2700 is more likely to beback drivable (cos(90)=1). The leads of the upper vertebra member teeth2450 and lower vertebra member teeth 2550 may also be advantageous inthat the rolling friction between the vertebra members 2420, 2520 andthe rotary drive screw 2700 is more likely to enable the rotary drivescrew 2700 to be back driven. Thus, in the event of an emergency, thesurgeon can pull on the upper and lower cables 2404, 2504 in theproximal direction to cause the firing member 2310 to fully retract fora quick “bailout”.

As indicated above, the relative control motions for the rotary drivesystem 2600, as well as the various cable-management systems employed inconnection with the firing system 2300 and the articulation controlsystem 2240, may be supported within a housing 2002 which may behandheld or comprise a portion of a larger automated surgical system.The firing system 2300, articulation control system 2240, and the rotarydrive system 2600 may, for example, be motor-controlled and operated byone or more control circuits.

One method of using the surgical instrument 10 may involve the use ofthe surgical instrument 10 to cut and staple target tissue within apatient using laparoscopic techniques. For example, one or more trocarsmay have been placed through the abdominal wall of a patient to provideaccess to a target tissue within the patient. The surgical end effector1000 may be inserted through one trocar and one or more cameras or othersurgical instruments may be inserted through the other trocar(s). Toenable the surgical end effector 1000 to pass through the trocarcannula, the surgical end effector 1000 is positioned in anunarticulated orientation and the jaws 1100 and 1200 must be closed. Toretain the jaws 1100 and 1200 in the closed position for insertionpurposes, for example, the rotary drive system 2600 may be actuated toapply the second rotary motion to the rotary drive screw 2700 to causethe firing member 2310 to move proximally from the starting position tomove the anvil 1210 (jaw 1200) to the closed position. See FIG. 44 . Therotary drive system 2600 is deactivated to retain the firing member 2310in that position. Once the surgical end effector has passed into theabdomen through the trocar, the rotary drive system 2600 may beactivated to cause the rotary drive screw 2700 to drive the firingmember 2310 distally back to the starting position wherein the anvilsprings 1270 will pivot the anvil 1210 to the open position. See FIG. 38.

Once inside the abdomen and before engaging the target tissue, thesurgeon may need to articulate the surgical end effector 1000 into anadvantageous position. The articulation control system 2240 is thenactuated to articulate the surgical end effector in one or more planesrelative to a portion of the elongate shaft assembly 2000 that isreceived within the cannula of the trocar. Once the surgeon has orientedthe surgical end effector 1000 in a desirable position, the articulationcontrol system 2240 is deactivated to retain the surgical end effector1000 in the articulated orientation. The surgeon may then use thesurgical end effector to grasp the target tissue or adjacent tissue byactivating the rotary drive system to rotate the rotary drive screw inthe second rotary direction to move the firing member proximally tocause the anvil 1210 to rapidly close to grasp the tissue between theanvil 1210 and the surgical staple cartridge 1300. The anvil 1210 may beopened by reversing the rotation of the rotary drive screw 2700. Thisprocess may be repeated as necessary until the target tissue has beproperly positioned between the anvil 1210 and the surgical staplecartridge 1300.

Once the target tissue has been positioned between the anvil 1210 andthe surgical staple cartridge, the surgeon may commence the closing andfiring process by activating the rotary drive system 2600 to drive thefiring member 2310 distally from the starting position. As the firingmember 2310 moves distally from the starting position, the firing member2310 applies a closure motion to the anvil 1210 and moves the anvil 1210from the open position to the closed position in the manners discussedabove. As the firing member 2310 moves distally, the firing member 2310retains the anvil 1210 in the closed position thereby clamping thetarget tissue between the anvil 1210 and the surgical staple cartridge1300. As the firing member 2310 moves distally, the firing member 2310contacts a sled 1312 supported in the surgical staple cartridge 1300 andalso drives the sled 1312 distally through the staple cartridge body1302. The sled 1312 serially drives rows of drivers supported in thestaple cartridge toward the clamped target tissue. Each driver hassupported thereon one or more surgical staples or fasteners which arethen driven through the target tissue and into forming contact with theunderside of the anvil 1210. As the firing member 2310 moves distally,the tissue cutting edge 2314 thereon cuts through the stapled tissue.

After the firing member 2310 has been driven distally to the endingposition within the surgical end effector 1000 (FIG. 45 ), the rotarydrive system 2600 is reversed which causes the firing member 2310 toretract proximally back to the home or starting position. Once thefiring member 2310 has returned to the starting position, the anvilsprings 1270 will pivot the anvil 1210 to the open position to enablethe surgeon to release the stapled tissue from the surgical end effector1000. Once the stapled tissue has been released, the surgical endeffector may be withdrawn out of the patient through the trocar cannula.To do so, the surgeon must first actuate the articulation control system2240 to return the surgical end effector 1000 to an unarticulatedposition and actuate the rotary drive system to drive the firing member2310 proximally from the home or starting position to close the jaws.Thereafter, the surgical end effector 1000 may be withdrawn through thetrocar cannula. If during the firing process or during the retractionprocess, the firing system becomes inoperative, the surgeon may retractthe firing member 2310 back to the starting position by applying apulling motion to the cables 2404, 2505 in the proximal direction in thevarious manners described herein.

FIGS. 46-68 illustrate another surgical instrument 22010 that in manyaspects is identical or very similar to the surgical instrument 10described above, except for the various differences discussed below.Like surgical instrument 10, surgical instrument 22010 may address manyof the challenges facing surgical instruments with articulatable endeffectors that are configured to cut and fasten tissue. In variousembodiments, the surgical instrument 22010 may comprise a handhelddevice. In other embodiments, the surgical instrument 22010 maycomprises an automated system sometimes referred to as arobotically-controlled system, for example. In various forms, thesurgical instrument 22010 comprises a surgical end effector 23000 thatis operably coupled to an elongate shaft assembly 24000. The elongateshaft assembly 24000 may be operably attached to a housing that ishandheld or otherwise comprises a portion of a robotic system as wasdiscussed above.

As can be seen in FIG. 49 , in one form, the surgical end effector 23000comprises a first jaw 23100 and a second jaw 23200. In the illustratedarrangement, the first jaw 23100 comprises an elongate channel 23110that comprises a proximal end 23112 and a distal end 23114 and isconfigured to operably support a surgical staple cartridge 1300 therein.The elongate channel 23110 has an open bottom to facilitate ease ofassembly and has a channel cover 23113 that is configured to be attachedthereto (welded, etc.) to cover the opening and add rigidity to theelongate channel 23110. In the illustrated arrangement, the second jaw23200 comprises an anvil 23210 that comprises an elongate anvil body23212 that comprises a proximal end 23214 and a distal end 23216. In onearrangement, an anvil cover 23213 is provided to facilitate assembly ofthe device and add rigidity to the anvil 23210 when it is attached(welded, etc.) to the anvil body 23212. The anvil body 23212 comprises astaple-forming undersurface 23218 that faces the first jaw 23100 and mayinclude a series of staple-forming pockets (not shown) that correspondsto each of the staples or fasteners in the surgical staple cartridge1300. The proximal end 23214 of the anvil body 23212 comprises an anvilmounting portion 23230 that includes a pair of laterally extendingmounting pins 23232 that are configured to be received in correspondingmounting cradles or pivot cradles 23120 formed in the proximal end 23112of the elongate channel 23110. The mounting pins 23232 are pivotallyretained within the mounting cradles 23120 by an anvil cap 23260 thatmay be attached to the proximal end 23112 of the elongate channel 23110by screws 23261. In other arrangements, the anvil cap 23260 may beattached to the elongate channel 23110 by welding, adhesive, etc. Sucharrangement facilitates pivotal travel of the anvil 23210 relative tothe surgical staple cartridge 1300 mounted in the elongate channel 23110about a pivot axis PA between an open position (FIG. 47 ) and a closedposition (FIG. 48 ). Such pivot axis PA may be referred to herein asbeing “fixed” in that the pivot axis does not translate or otherwisemove as the anvil 23210 is pivoted from an open position to a closedposition.

In the illustrated arrangement, the anvil 23210 is moved to the openposition by a pair of anvil springs 23270 that are supported within theproximal end 23112 of the elongate channel 23110. See FIGS. 49 and 62 .The springs 23270 are positioned to apply a pivotal biasing force tocorresponding portions of the anvil 23210 to apply opening forcesthereto. See FIG. 47 .

In the illustrated arrangement, the elongate shaft assembly 24000defines a shaft axis SA and comprises a proximal shaft portion 24100that may operably interface with a housing of the control portion (e.g.,handheld unit, robotic tool driver, etc.) of the surgical instrument22010. The elongate shaft assembly 24000 further comprises anarticulation joint 24200 that is attached to the proximal shaft portion24100 and the surgical end effector 23000. In various instances, theproximal shaft portion 24100 comprises a hollow outer tube 24110 thatmay be operably coupled to a housing in the various manners discussedabove. As can be seen in FIG. 49 , the proximal shaft portion 24100 mayfurther comprise a rigid proximal support shaft 24120 that is supportedwithin the hollow outer tube 24110 and extends from the housing to thearticulation joint 24200. The rigid proximal support shaft 24120 maycomprise a first half 24120A and a second half 24120B that may becoupled together by, for example, welding, adhesive, etc. The rigidproximal support shaft 24120 comprises a proximal end 24122 and a distalend 24124 and includes an axial passage 24126 that extends therethroughfrom the proximal end 24122 to the distal end 24124.

As was discussed above, many surgical end effectors employ a firingmember that is pushed distally through a surgical staple cartridge by anaxially movable firing beam. The firing beam is commonly attached to thefiring member in the center region of the firing member body. Thisattachment location can introduce an unbalance to the firing member asit is advanced through the end effector. Such unbalance can lead toundesirable friction between the firing member and the end effectorjaws. The creation of this additional friction may require anapplication of a higher firing force to overcome such friction as wellas can cause undesirable wear to portions of the jaws and/or the firingmember. An application of higher firing forces to the firing beam mayresult in unwanted flexure in the firing beam as it traverses thearticulation joint. Such additional flexure may cause the articulationjoint to de-articulate—particularly when the surgical end effector isarticulated at relatively high articulation angles. The surgicalinstrument 22010 employs a firing system 24300 that is identical to orvery similar in many aspects as firing system 2300 described above. Assuch, only those aspects of the firing system 24300 needed to understandthe operation of the surgical instrument 22010 will be discussed below.

As can be seen in FIGS. 50-54 , in at least one embodiment, the firingsystem 24300 comprises a firing member 24310 that includes avertically-extending firing member body 24312 that comprises a topfiring member feature 24320 and a bottom firing member feature 24350. Atissue cutting blade 24314 is attached to or formed in thevertically-extending firing member body 24312. See FIGS. 50 and 51 . Inat least one arrangement, it is desirable for the firing member 24310 topass through the anvil body 23212 with low friction, high strength andhigh stiffness. In the illustrated arrangement, the top firing memberfeature 24320 comprises a T-shaped body 24322 that has two laterallyextending tabs 24323 protruding therefrom and a top axial passage 24324extending therethrough. See FIG. 53 . The bottom firing member feature24350 comprises a T-shaped body 24352 that has two laterally extendingtabs 24353 protruding therefrom and a bottom axial passage 24354extending therethrough. See FIG. 50 . In at least one arrangement, thetop firing member feature 24320 and the bottom firing member feature24350 are integrally formed with the vertically-extending firing memberbody 24312. As can be seen in FIG. 54 , the anvil body 23212 comprisesan axially extending anvil slot 23240 that defines two opposed ledges23241 for slidably receiving the laterally extending tabs 24323 thereon.Similarly, the elongate channel 23110 comprises an axially extendingchannel slot 23140 that defines axially extending channel ledges 23141that are configured to slidably receive the laterally extending tabs24353 thereon.

In the illustrated arrangement, the firing system 24300 comprises anupper flexible spine assembly 24400 that is operably coupled to the topfiring member feature 24320 of the firing member 24310. In at least oneembodiment, the upper flexible spine assembly 24400 comprises an upperseries 24410 of upper vertebra members 24420 that are loosely coupledtogether by an upper flexible coupler member 24440 that extends througheach of the upper vertebra members 24420 and is attached to the topfiring member feature 24320.

As can be seen in FIG. 52 , each upper vertebra member 24420 issubstantially T-shaped when viewed from an end thereof. In one aspect,each upper vertebra member 24420 comprises an upper vertebra bodyportion 24422 that has a proximal end 24424 and a distal end 24428. Eachupper vertebra member 24420 further comprises a downwardly extendingupper drive feature or upper vertebra member tooth 24450 that protrudesfrom the upper vertebra body portion 24422. Each upper vertebra membertooth 24450 has a helix-shaped proximal upper face portion 24452 and ahelix-shaped distal upper face portion 24454. Each proximal end 24424 ofthe upper vertebra body portions 24422 has an arcuate or slightlyconcave curved shape and each distal end 24428 has an arcuate orslightly convex curved shape. When arranged in the upper series 24410,the convex distal end 24428 on one upper vertebra member 24420 contactsand mates with the concave proximal end 24424 on an adjacent uppervertebra member 24420 in the upper series 24410 to maintain the uppervertebra members 24420 roughly in alignment so that the helix-shapedproximal upper face portion 24452 and a helix-shaped distal upper faceportion 24454 on each respective upper vertebra member tooth 24450 canbe drivingly engaged by a rotary drive screw 2700 in the various mannersdisclosed herein. These curved mating surfaces on the upper vertebramembers 24420 allow the upper vertebras members 24420 to better transferloads between themselves even when they tilt.

In at least one embodiment, an upper alignment member 24480 is employedto assist with the alignment of the upper vertebra members 24420 in theupper series 24410. In one arrangement, the alignment member 24480comprises a spring member or metal cable which may be fabricated fromNitinol wire, spring steel, etc., and be formed with a distal upperlooped end 24482 and two upper leg portions 24484 that extend throughcorresponding upper passages 24425 in each upper vertebra body portion24422. The upper flexible coupler member 24440 extends through an upperpassage 24429 in each of the upper vertebra members 24420 to be attachedto the firing member 24310. In particular, a distal end portion 24442extends through the top axial passage 24324 in the top firing memberfeature 24320 and is secured therein by an upper retention lug 24444. Aproximal portion of the upper flexible coupler member 24440 mayinterface with a corresponding rotary spool or cable-management systemof the various types and designs disclosed herein that serve to payoutand take up the upper flexible coupler member 24440 to maintain adesired amount of tension therein during operation and articulation ofthe surgical end effector 23000. The cable management system may bemotor powered or manually powered (ratchet arrangement, etc.) tomaintain a desired amount of tension in the upper flexible couplermember 24440. The amount of tension in each flexible coupler member mayvary depending upon the relative positioning of the surgical endeffector 23000 to the elongate shaft assembly 24000.

The firing system 24300 further comprises a lower flexible spineassembly 24500 that is operably coupled to the bottom firing memberfeature 24350. The lower flexible spine assembly 24500 comprises a lowerseries 24510 of lower vertebra members 24520 that are loosely coupledtogether by a lower flexible coupler member 24540 that extends througheach of the lower vertebra members 24520 and is attached to the bottomfiring member feature 24350. As can be seen in FIG. 52 , each lowervertebra member 24520 is substantially T-shaped when viewed from an endthereof. In one aspect, each lower vertebra member 24520 comprises alower vertebra body portion 24522 that has a proximal end 24524 and adistal end 24528. Each lower vertebra member 24520 further comprises anupwardly extending lower drive feature or lower vertebra member tooth24550 that protrudes from the lower vertebra body portion 24522. Eachlower vertebra member tooth 24550 has a helix-shaped proximal lower faceportion 24552 and a helix-shaped distal lower face portion 24554. Theproximal end 24524 of each lower vertebra body portions 24522 has anarcuate or slightly concave curved shape and each distal end 24528 hasan arcuate or slightly convex curved shape. When arranged in the lowerseries 24510, the convex distal end 24528 on one lower vertebra member24520 contacts and mates with the concave proximal end 24524 on anadjacent lower vertebra member 24520 in the lower series 24510 tomaintain the lower vertebra members 24520 roughly in alignment so thatthe helix-shaped proximal lower face portion 24552 and a helix-shapeddistal lower face portion 24554 on each respective lower vertebra membertooth 24550 can be drivingly engaged by the rotary drive screw 2700 inthe various manners disclosed herein. These curved mating surfaces onthe lower vertebra members 24520 allow the lower vertebra members 24520to better transfer loads between themselves even when they tilt.

In at least one embodiment, a lower alignment member 24580 is employedto assist with the alignment of the lower vertebra members 24520 in thelower series 24510. In one arrangement, the lower alignment member 24580comprises a spring member or metal cable which may be fabricated fromNitinol wire, spring steel, etc., and be formed with a distal lowerlooped end 24582 and two lower leg portions 24584 that extend throughcorresponding lower passages 24525 in each lower vertebra body portion24522. The lower flexible coupler member 24540 extends through thebottom axial passage 24529 in each of the lower vertebra members 24520to be attached to the firing member 24310. In particular, a distal endportion 24542 of the lower flexible coupler member 24540 extends throughthe bottom axial passage 24354 in the bottom firing member feature 24350and is secured therein by a lower retention lug 24544. A proximalportion of the lower flexible coupler member 24540 may interface with acorresponding rotary spool or cable-management system of the varioustypes and designs disclosed herein that serve to payout and take up thelower flexible coupler member 24540 to maintain a desired amount oftension therein during operation and articulation of the surgical endeffector 23000. The cable management system may be motor powered ormanually powered (ratchet arrangement, etc.) to maintain a desiredamount of tension in the lower flexible coupler member 24540. The amountof tension in each flexible coupler member may vary depending upon therelative positioning of the surgical end effector 23000 to the elongateshaft assembly 24000.

In accordance with at least one aspect, a large surface area isadvantageous for distributing the force between the vertebra memberswhen they push so that the vertebra members cannot twist relative toeach other. The available area in the anvil and channel is limited andthe anvil and channel must remain stiff. The T-shaped upper vertebramembers 24420 and the T-shaped lower vertebra members 24520 are designedto fit in the limited spaces available in the anvil 23210 and theelongate channel 23110 while ensuring that there is a large amount ofarea to distribute the firing loads. The curved surfaces on each uppervertebra member 24420 and each lower vertebra member 24520 allow each ofthose vertebras to better transfer loads between themselves even whenthey tilt. The upper alignment member 24480 and the lower alignmentmember 24580 may also serve to prevent the upper vertebra members 24420and the lower vertebra members 24520 from twisting relative to eachother. The large surface area may also help to prevent galling of thevertebra members and/or the anvil and channel. The upper flexible spineassembly 24400 and the lower flexible spine assembly 24500 otherwiseoperably interface with the rotary drive screw 2700 arrangements asdisclosed herein. The upper flexible coupler member 24440 and the lowerflexible coupler member 24540 may also be used in the manners discussedabove to retract the firing member 24310 back to its starting positionif, during a firing stroke, the firing drive system 24300 fails.

As can be seen in FIG. 51 , the top firing member feature 24320 on thefiring member 24310 comprises a distal upper firing member tooth segment24330 that is equivalent to one half of an upper vertebra member tooth24450 on each upper vertebra member 24420. In addition, two proximalupper firing member teeth 24336 that are identical to an upper vertebramember tooth 24450 on each upper vertebra member 24420 are spaced fromthe distal upper firing member tooth segment 24330. The distal upperfiring member tooth segment 24330 and the proximal upper firing memberteeth 24336 may each be integrally formed with the top firing memberfeature 24320 of the firing member 24310. Likewise, the bottom firingmember feature 24350 of the firing member 24310 comprises a distal lowerfiring member tooth 24360 and two proximal lower firing member teeth24366 that are integrally formed on the bottom firing member feature24350. For example, in at least one arrangement, the firing member 24310with the rigidly attached teeth 24330, 24336, 24360, and 24366 may befabricated at one time as one unitary component using conventional metalinjection molding techniques. The person of ordinary skill in the artwill recognize that the firing member 24310 operates in essentially thesame manner as the firing member 2310 as was described in detail herein.

Turning now to FIGS. 55-58 , in accordance with at least one aspect, thearticulation joint 24200 comprises a movable exoskeleton assembly 24800.In one form, the movable exoskeleton assembly 24800 comprises a series24802 of movably interfacing annular rib members 24810. As can be seenin FIGS. 55-57 , each annular rib member 24810 comprises a first orproximal face 24820 that comprises a convex or domed portion 24822. Eachannular rib member 24810 further comprises a second or distal face 24830that is concave or dished. Each annular rib member 24810 furthercomprises an upper spine passage 24840 that is configured to accommodatepassage of the upper flexible spine assembly 24400 therethrough and alower spine passage 24842 that is configured to accommodate passage ofthe lower flexible spine assembly 24500 therethrough. In addition, eachannular rib member 24810 further comprises four articulation passages24850, 24852, 24854, and 24856 to accommodate passage of articulationactuators in the form of articulation cables 24242, 22446, 24250, and24254 therethrough. See FIG. 49 . Each annular rib member 24810 furthercomprises a central drive passage 24860 that is configured toaccommodate passage of the constant velocity (CV) drive shaft assembly2620 therethrough.

As can be seen in FIG. 58 , the movable exoskeleton assembly 24800comprises a proximal attachment rib 24870 that is configured to attachthe movable exoskeleton assembly 24800 to the distal end 24124 of theproximal support shaft 24120 by cap screws 24880 or other suitablefastener arrangements. The proximal attachment rib 24870 comprises afirst or distal face 24872 that is concave or dished to receive ormovably interface with the convex or domed portion 24822 of the proximalface 24820 of a proximal-most annular rib member 24810P. Similarly, themovable exoskeleton assembly 24800 comprises a distal attachment rib24890 that is configured to attach the movable exoskeleton assembly24800 to the proximal end 23112 of the elongate channel 23110 by capscrews 24882 or other suitable fasteners. The distal attachment rib24890 comprises a first or proximal face 24892 that comprises a convexor domed portion 24894 that configured to be received in or movablyinterface with the concave or dished distal face 24832 of a distal-mostannular rib member 24810D. In various embodiments, the annular ribmembers 24810, 24810P, and 24810D may be fabricated from any suitablemetal (e.g., stainless steel, titanium, etc.) or other suitablematerial. The annular rib members 24810, 24810P, and 24810D may beformed by suitable drawing or forming operations, by machining orcasting. The proximal faces 24820 and the distal faces 24830 may bepolished or otherwise finished to a desirable smooth finish to reducefriction and facilitate movement between the annular rib members 24810,24810P, and 24810D. In accordance with one aspect, all edges on eachannular rib member 24810, 24810P, 24810D are rounded to facilitaterelative movement between the annular rib members. The proximalattachment rib 24870 and the distal attachment rib 24890 may be formedwith similar attributes.

The surgical instrument 22010 also comprises an articulation system24240 that is configured to apply articulation motions to the surgicalend effector 23000 to articulate the surgical end effector 23000relative to the elongate shaft assembly 24000. In at least onearrangement, for example, as mentioned above, the articulation system24240 comprises four articulation cables 24242, 24246, 24250, and 24254that extend through the elongate shaft assembly 2400. See FIG. 49 . Inthe illustrated arrangement, the articulation cables 24242, 24246 passthrough the proximal attachment rib 24870 and through each of theannular rib members 24810P, 24810, and 24810D to be secured to thedistal attachment rib 24890. In one arrangement for example, each of thearticulation cables 24242, 24246 are secured to the distal attachmentrib 24890 by corresponding attachment lugs 24243. See FIGS. 61 and 63 .Likewise, the articulation cables 24250 and 24254 extend through theproximal attachment rib 24870 and through each of the annular ribmembers 24810P, 24810, and 24810D to be secured to the distal attachmentrib 24890 by corresponding attachment lugs 24243.

In one arrangement, each of the articulation cables 24242, 24246, 24250,and 24254 extend through corresponding coil springs 24896 that aresupported in cavities 24125 in the distal end 24124 of the rigidproximal support shaft 24120. In addition, each coil spring 24896 isassociated with a tensioning lug 24897 that is also journaled onto eachrespective articulation cable 24242, 24246, 24250, and 24524 and issecured thereon to attain a desired amount of compression in each spring24896 which serves to retain the annular rib members 24810P, 24810, and24810D in movable engagement with each other and with the proximalattachment rib 24870 and the distal attachment rib 24890. The cables24242, 24246, 24250, and 24254 operably interface with an articulationcontrol system that is supported in the housing of the surgicalinstrument 22010. For example, as was discussed above, a proximalportion of each cable 24242, 24246, 24250, and 24254 may be spooled on acorresponding rotary spool or cable-management system 2007 (FIG. 2 ) inthe housing portion of the surgical instrument 22010 that is configuredto payout and retract each cable 24242, 24246, 24250, and 24254 indesired manners. The spools/cable management system may be motor poweredor manually powered (ratchet arrangement, etc.). FIG. 59 illustrates thearticulation joint 24200 in an unarticulated position and FIG. 60illustrates the articulation joint in one articulated configuration.Such arrangement permits the surgical end effector 23000 to bearticulated through multiple articulation planes relative to theelongate shaft assembly 24000.

As can be seen in FIGS. 49, 58, and 64 , the surgical instrument 22010employs a constant velocity (CV) drive shaft assembly 2620 that spans orextends axially through the articulation joint 24200. The operation andconstruction of the CV drive shaft assembly 2620 was described in detailabove and will not be repeated here beyond what is necessary tounderstand the operation of the surgical instrument 22010. Briefly asdescribed above, the CV drive shaft assembly 2620 comprises a proximalCV drive assembly 2630 and a distal CV drive shaft 2670. The proximal CVdrive assembly 2630 comprises a proximal shaft segment 2632 thatconsists of an attachment shaft 2634 that is configured to benon-rotatably received within a similarly-shaped coupler cavity 2616 inthe distal end 2614 of the proximal rotary drive shaft 2610. Theproximal shaft segment 2632 operably interfaces with a series 2640 ofmovably coupled drive joints 2650. As can be seen in FIG. 58 as was alsodescribed previously, to ensure that the drive joints 2650 are engagedwith each other, a proximal drive spring 2740 is employed to apply anaxial biasing force to the series 2640 of drive joints 2650. Forexample, as can be seen in FIG. 58 , proximal drive spring 2740 ispositioned between the proximal mounting bushing 2734 and a supportflange that is formed between the distal socket portion 2636 and aproximal barrel portion 2638 of the proximal shaft segment 2632. In onearrangement, the proximal drive spring 2740 may comprise an elastomericO-ring received on the proximal barrel portion 2638 of the proximalshaft segment 2632. The proximal drive spring 2740 lightly biases thedrive joints 2650 together to decrease any gaps that occur duringarticulation. This ensures that the drive joints 2650 transfer loadstorsionally. It will be appreciated, however, that in at least onearrangement, the proximal drive spring 2740 does not apply a high enoughaxial load to cause firing loads to translate through the articulationjoint 2200.

To further prevent the drive joints 2650 from buckling duringarticulation, the series 2640 of movably coupled drive joints 2650extend through at least one low friction drive cover 24730 that extendsthrough the central drive passage 24860 in each of the annular ribmembers 24810. In the arrangement depicted in FIGS. 63 and 65 , thedrive cover 24730 comprises an outer and inner cut hypotube 24732. Suchhypotube 24732 may be fashioned from metal (e.g., stainless steel, etc.)and have multiple series of cuts or slits therein that may be made usinglaser cutter arrangements. In the illustrated arrangement, the hypotube24732 may be fabricated with an upper relief passage 24734 that providesclearance for the upper flexible spine assembly 24400 to pass thereoverduring operation while the surgical end effector 23000 is in anarticulated position and articulated positions. In addition, thehypotube 24732 may have a lower relief passage 24736 to provide similarclearance for the lower flexible spine assembly 24500. As can also beseen in FIG. 65 , the hypotube 24732 may be shaped with diametricallyopposed lateral tab portions 24738 to provide lateral stability duringarticulation. FIG. 66 illustrates an alternative drive cover 24730′ thatcomprises an inner cut hypotube 24732′. FIGS. 58, 67, 68 , and 69illustrate an alternative drive cover 24730″ that comprises flexibleheat shrink tubing 24732″ that is applied over the constant velocity(CV) drive shaft assembly 2620. In still other arrangements, the drivecover may comprise a coiled spring or coiled member as well.

Various embodiments of the present disclosure provide advantages overprevious surgical endocutter configurations that are capable ofarticulation. For example, pushing a firing member forward in anarticulating end effector generally requires a lot of force and thatforce must be balanced. For example, when firing the firing member at anangle of greater than sixty degrees, it becomes very difficult to push abeam through the articulation joint. The joint also experiencessignificant loads which may cause the articulation joint tode-articulate. By employing an upper flexible drive arrangement and alower flexible drive arrangement that are each flexible through thearticulation joint, but then become rigid when they are distal to thearticulation joint can allow for a large degree of articulation (e.g.,articulation angles over seventy degrees) while applying balanced loadsto the firing member that are constrained to the firing member and notto the articulation joint. Stated another way, torsional loads areapplied proximal to the articulation joint instead of longitudinal loadswhich could lead to de-articulation of the end effector. The torsionalloads are converted to longitudinal loads at a position that is distalto the articulation joint. Thus, the rotary drive screw serves toactually convert torsional motion or loads to longitudinal loads thatare applied to the firing member at a location that is distal to thearticulation joint.

Further, by longitudinally breaking up the threaded drive arrangements,the threaded drive arrangements pass through the articulation jointwhile also effectively decreasing the length of the surgical endeffector. For example, each single vertebra tooth is significantlyshorter than multiple pitches rigidly connected. The vertebra can angleas they pass through the articulation joint. This flexibleinterconnection enables the rotary drive screw to be closely positionedto the articulation joint as compared to being significantly spacedtherefrom if all of the pitches were rigidly connected.

Example 1—A surgical instrument comprising an elongate shaft. A surgicalend effector is coupled to the elongate shaft by an articulation jointthat is configured to facilitate selective articulation of the surgicalend effector relative to the elongate shaft. The surgical end effectorcomprises a first jaw and a second jaw that is configured to moverelative to the first jaw between an open position and a closedposition. A firing member is supported for axial travel within thesurgical end effector between a starting position and an endingposition. The surgical instrument further comprises an upper flexiblespine assembly that is attached to a top portion of the firing member. Alower flexible spine assembly is attached to a bottom portion of thefiring member. A rotary drive member operably interfaces with the upperflexible spine assembly at an upper location. The rotary drive memberalso operably interfaces with the lower flexible spine assembly at alower location. The upper location and the lower location are distal tothe articulation joint. The rotary drive member is configured to causethe upper flexible spine assembly and the lower flexible spine assemblyto apply axial drive motions to the firing member to move the firingmember between the starting position and the ending position.

Example 2—The surgical instrument of Example 1, wherein the rotary drivemember is centrally disposed between the upper flexible spine assemblyand the lower flexible spine assembly.

Example 3—The surgical instrument of Examples 1 or 2, wherein the upperflexible spine assembly comprises an upper series of upper vertebramembers that are loosely coupled together and the lower flexible spineassembly comprises a lower series of lower vertebra members that areloosely coupled together.

Example 4—The surgical instrument of Example 3, wherein the uppervertebra members are movably supported relative to each other by anupper flexible coupler member that is coupled to the top portion of thefiring member and extends through each upper vertebra member. The lowervertebra members are movably supported relative to each other by a lowerflexible coupler member that is coupled to the bottom portion of thefiring member and extends through each lower vertebra member.

Example 5—The surgical instrument of Example 4, wherein each uppervertebra member comprises an upper vertebra body portion that defines anupper proximal end and an upper distal end. An upper hollow passageextends through the upper vertebra body portion between the upperproximal end and the upper distal end to permit the upper flexiblecoupler member to extend therethrough. An upper proximal mating featureis provided on the upper proximal end and an upper distal mating featureis provided on the upper distal end. The upper proximal mating featureon each upper vertebra member is configured to movably interface withthe upper distal mating feature on an adjacent upper vertebra member. Anupper vertebra drive feature is configured to operably engage the rotarydrive member.

Example 6—The surgical instrument of Example 5, wherein the upperproximal mating feature comprises an upper concave recess in the upperproximal end of the upper vertebra body portion. The upper distal matingfeature comprises an upper convex protrusion on the upper distal end ofthe upper vertebra body portion. The upper convex protrusion on eachupper vertebra member is sized and shaped to matingly engage the upperconcave recess in an adjacent upper vertebra member.

Example 7—The surgical instrument of Examples 5 or 6, wherein the eachlower vertebra member comprises a lower vertebra body portion thatdefines a lower proximal end and a lower distal end. A lower hollowpassage extends through the lower vertebra body portion between thelower proximal end and the lower distal end to permit the lower flexiblecoupler member to extend therethrough. A lower proximal mating featureis provided on the lower proximal end and a lower distal mating featureis provided on the lower distal end. The lower proximal mating featureon each lower vertebra member is configured to movably interface withthe lower distal mating feature on an adjacent lower vertebra member. Alower vertebra drive feature is configured to operably engage the rotarydrive member.

Example 8—The surgical instrument of Example 7, wherein the lowerproximal mating feature comprises a lower concave recess in the lowerproximal end of the lower vertebra body portion and the lower distalmating feature comprises a lower convex protrusion on the lower distalend of the lower vertebra body portion. The lower convex protrusion oneach lower vertebra member is sized and shaped to matingly engage thelower concave recess in an adjoining lower vertebra member.

Example 9—The surgical instrument of Examples 7 or 8, wherein the uppervertebra drive feature comprises an upper tooth that is configured tointerface with the rotary drive member, and wherein the lower vertebradrive feature comprises a lower tooth that is configured to interfacewith the rotary drive member.

Example 10—The surgical instrument of Example 9, wherein the rotarydrive member comprises a rotary body portion that has a helical drivemember on an external surface thereof. The helical drive member isconfigured to engage an upper helical surface that is formed on eachupper tooth and a lower helical surface on each lower tooth.

Example 11—The surgical instrument of Examples 3, 4, 5, 6, 7, 8, 9 or10, further comprising an upper vertebra biaser that is configured toapply a continuous upper compression to the upper series of uppervertebra members to retain the upper vertebra members in the upperseries of upper vertebra members in movable contact with each other. Thesurgical instrument further comprises a lower vertebra biaser that isconfigured to apply a continuous lower compression to the lower seriesof lower vertebra members to retain the lower vertebra members in thelower series of lower vertebra members in movable contact with eachother.

Example 12—The surgical instrument of Example 10, wherein the upperhelical surface comprises two different pitches.

Example 13—The surgical instrument of Examples 4, 5, 6, 7, 8, 9, 10, 11or 12, wherein the upper flexible coupler member and the lower flexiblecoupler member are configured to retract the firing member from aposition that is distal to the starting position by applying retractionmotions to each of the upper flexible coupler member and the lowerflexible coupler member in a proximal direction.

Example 14—The surgical instrument of Examples 3, 4, 5, 6, 7, 8, 9, 10,11, 12 or 13, wherein the articulation joint comprises an articulationjoint length and wherein the upper series of upper vertebra memberscomprises an upper series length that is greater than or equal to thearticulation joint length plus a distance from the starting position tothe ending position of the firing member. The lower series of lowervertebra members comprises a lower series length that is greater than orequal to the articulation joint length plus the distance from thestarting position to the ending position of the firing member.

Example 15—The surgical instrument of Examples 3, 4, 5, 6, 7, 8, 9, 10,11, 12, 13 or 14, further comprising an upper sleeve that extends from aproximal end of the surgical end effector and spans the articulationjoint. The upper sleeve is axially movable relative to the surgical endeffector and is configured to slidably support a portion of the upperseries of upper vertebra members that spans the articulation joint. Alower sleeve extends from the proximal end of the surgical end effectorand spans the articulation joint. The lower sleeve is axially movablerelative to the surgical end effector and is configured to slidablysupport another portion of the lower series of lower vertebra membersthat spans the articulation joint.

Example 16—A surgical instrument that comprises an elongate shaft thathas a surgical end effector coupled thereto by an articulation jointthat is configured to facilitate selective articulation of the surgicalend effector relative to the elongate shaft. The surgical end effectorcomprises a firing member that is supported for axial travel within thesurgical end effector between a starting position and an endingposition. A rotary drive member is rotatably supported at a locationthat is distal to the articulation joint. An upperlongitudinally-segmented nut assembly is attached to a top portion ofthe firing member and is in threaded engagement with the rotary drivemember at an upper location that is distal to the articulation jointsuch that rotation of the rotary drive member causes the upperlongitudinally-segmented nut assembly to apply an upper axial drivemotion to the firing member. The upper longitudinally-segmented nutassembly is flexible to accommodate articulation of the surgical endeffector. A lower longitudinally-segmented nut assembly is attached to abottom portion of the firing member and is in threaded engagement withthe rotary drive member at a lower location that is distal to thearticulation joint such that rotation of the rotary drive member causesthe lower longitudinally-segmented nut assembly to apply a lower axialdrive motion to the firing member. The lower longitudinally-segmentednut assembly is flexible to accommodate articulation of the surgical endeffector.

Example 17—The surgical instrument of Example 16, wherein the upperlongitudinally-segmented nut assembly comprises an upper series of uppervertebra members that are movably supported relative to each other by anupper flexible coupler member that is coupled to the top portion of thefiring member and extends through each upper vertebra member. The lowerlongitudinally-segmented nut assembly comprises a lower series of lowervertebra members that are movably supported relative to each other by alower flexible coupler member that is coupled to the bottom portion ofthe firing member and extends through each lower vertebra member.

Example 18—The surgical instrument of Examples 16 or 17, wherein therotary drive member comprises a helical thread that comprises at leasttwo different pitches.

Example 19—The surgical instrument of Examples 17 or 18, furthercomprising means for permitting the upper vertebra members and the lowervertebra members that traverse the articulation joint to move out ofaxial alignment while facilitating serial threaded engagement with therotary drive member.

Example 20—A surgical instrument that comprises an elongate shaft thathas a surgical end effector coupled thereto by an articulation jointconfigured to facilitate selective articulation of the surgical endeffector relative to the elongate shaft. The surgical end effectorcomprises a firing member that is supported for axial travel within thesurgical end effector between a starting position and an endingposition. A rotary drive member is rotatably supported at a locationthat is distal to the articulation joint. A flexible drive assembly issupported by the elongate shaft such that it axially traverses thearticulation joint and is configured to accommodate articulation of thesurgical end effector about the articulation joint. The flexible driveassembly is in threaded engagement with the rotary drive member at adrive location that is distal to the articulation joint such thatrotation of the rotary drive member causes the flexible drive assemblyto apply an axial drive motion to the firing member.

As used in any aspect herein, the term “control circuit” may refer to,for example, hardwired circuitry, programmable circuitry (e.g., acomputer processor including one or more individual instructionprocessing cores, processing unit, processor, microcontroller,microcontroller unit, controller, digital signal processor (DSP),programmable logic device (PLD), programmable logic array (PLA), orfield programmable gate array (FPGA)), state machine circuitry, firmwarethat stores instructions executed by programmable circuitry, and anycombination thereof. The control circuit may, collectively orindividually, be embodied as circuitry that forms part of a largersystem, for example, an integrated circuit (IC), an application-specificintegrated circuit (ASIC), a system on-chip (SoC), desktop computers,laptop computers, tablet computers, servers, smart phones, etc.Accordingly, as used herein “control circuit” includes, but is notlimited to, electrical circuitry having at least one discrete electricalcircuit, electrical circuitry having at least one integrated circuit,electrical circuitry having at least one application specific integratedcircuit, electrical circuitry forming a general purpose computing deviceconfigured by a computer program (e.g., a general purpose computerconfigured by a computer program which at least partially carries outprocesses and/or devices described herein, or a microprocessorconfigured by a computer program which at least partially carries outprocesses and/or devices described herein), electrical circuitry forminga memory device (e.g., forms of random access memory), and/or electricalcircuitry forming a communications device (e.g., a modem, communicationsswitch, or optical-electrical equipment). Those having skill in the artwill recognize that the subject matter described herein may beimplemented in an analog or digital fashion or some combination thereof.

While several forms have been illustrated and described, it is not theintention of Applicant to restrict or limit the scope of the appendedclaims to such detail. Numerous modifications, variations, changes,substitutions, combinations, and equivalents to those forms may beimplemented and will occur to those skilled in the art without departingfrom the scope of the present disclosure. Moreover, the structure ofeach element associated with the described forms can be alternativelydescribed as a means for providing the function performed by theelement. Also, where materials are disclosed for certain components,other materials may be used. It is therefore to be understood that theforegoing description and the appended claims are intended to cover allsuch modifications, combinations, and variations as falling within thescope of the disclosed forms. The appended claims are intended to coverall such modifications, variations, changes, substitutions,modifications, and equivalents.

One or more components may be referred to herein as “configured to,”“configurable to,” “operable/operative to,” “adapted/adaptable,” “ableto,” “conformable/conformed to,” etc. Those skilled in the art willrecognize that “configured to” can generally encompass active-statecomponents and/or inactive-state components and/or standby-statecomponents, unless context requires otherwise.

Those skilled in the art will recognize that, in general, terms usedherein, and especially in the appended claims (e.g., bodies of theappended claims) are generally intended as “open” terms (e.g., the term“including” should be interpreted as “including but not limited to,” theterm “having” should be interpreted as “having at least,” the term“includes” should be interpreted as “includes but is not limited to,”etc.). It will be further understood by those within the art that if aspecific number of an introduced claim recitation is intended, such anintent will be explicitly recited in the claim, and in the absence ofsuch recitation no such intent is present. For example, as an aid tounderstanding, the following appended claims may contain usage of theintroductory phrases “at least one” and “one or more” to introduce claimrecitations. However, the use of such phrases should not be construed toimply that the introduction of a claim recitation by the indefinitearticles “a” or “an” limits any particular claim containing suchintroduced claim recitation to claims containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (e.g., “a” and/or “an” should typically be interpreted to mean “atleast one” or “one or more”); the same holds true for the use ofdefinite articles used to introduce claim recitations.

In addition, even if a specific number of an introduced claim recitationis explicitly recited, those skilled in the art will recognize that suchrecitation should typically be interpreted to mean at least the recitednumber (e.g., the bare recitation of “two recitations,” without othermodifiers, typically means at least two recitations, or two or morerecitations). Furthermore, in those instances where a conventionanalogous to “at least one of A, B, and C, etc.” is used, in generalsuch a construction is intended in the sense one having skill in the artwould understand the convention (e.g., “a system having at least one ofA, B, and C” would include but not be limited to systems that have Aalone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). In those instances where aconvention analogous to “at least one of A, B, or C, etc.” is used, ingeneral such a construction is intended in the sense one having skill inthe art would understand the convention (e.g., “a system having at leastone of A, B, or C” would include but not be limited to systems that haveA alone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). It will be furtherunderstood by those within the art that typically a disjunctive wordand/or phrase presenting two or more alternative terms, whether in thedescription, claims, or drawings, should be understood to contemplatethe possibilities of including one of the terms, either of the terms, orboth terms unless context dictates otherwise. For example, the phrase “Aor B” will be typically understood to include the possibilities of “A”or “B” or “A and B.”

With respect to the appended claims, those skilled in the art willappreciate that recited operations therein may generally be performed inany order. Also, although various operational flow diagrams arepresented in a sequence(s), it should be understood that the variousoperations may be performed in other orders than those which areillustrated, or may be performed concurrently. Examples of suchalternate orderings may include overlapping, interleaved, interrupted,reordered, incremental, preparatory, supplemental, simultaneous,reverse, or other variant orderings, unless context dictates otherwise.Furthermore, terms like “responsive to,” “related to,” or otherpast-tense adjectives are generally not intended to exclude suchvariants, unless context dictates otherwise.

It is worthy to note that any reference to “one aspect,” “an aspect,”“an exemplification,” “one exemplification,” and the like means that aparticular feature, structure, or characteristic described in connectionwith the aspect is included in at least one aspect. Thus, appearances ofthe phrases “in one aspect,” “in an aspect,” “in an exemplification,”and “in one exemplification” in various places throughout thespecification are not necessarily all referring to the same aspect.Furthermore, the particular features, structures or characteristics maybe combined in any suitable manner in one or more aspects.

Any patent application, patent, non-patent publication, or otherdisclosure material referred to in this specification and/or listed inany Application Data Sheet is incorporated by reference herein, to theextent that the incorporated materials is not inconsistent herewith. Assuch, and to the extent necessary, the disclosure as explicitly setforth herein supersedes any conflicting material incorporated herein byreference. Any material, or portion thereof, that is said to beincorporated by reference herein, but which conflicts with existingdefinitions, statements, or other disclosure material set forth hereinwill only be incorporated to the extent that no conflict arises betweenthat incorporated material and the existing disclosure material.

In summary, numerous benefits have been described which result fromemploying the concepts described herein. The foregoing description ofthe one or more forms has been presented for purposes of illustrationand description. It is not intended to be exhaustive or limiting to theprecise form disclosed. Modifications or variations are possible inlight of the above teachings. The one or more forms were chosen anddescribed in order to illustrate principles and practical application tothereby enable one of ordinary skill in the art to utilize the variousforms and with various modifications as are suited to the particular usecontemplated. It is intended that the claims submitted herewith definethe overall scope.

The surgical instrument systems described herein have been described inconnection with the deployment and deformation of staples; however, theembodiments described herein are not so limited. Various embodiments areenvisioned which deploy fasteners other than staples, such as clamps ortacks, for example. Moreover, various embodiments are envisioned whichutilize any suitable means for sealing tissue. For instance, an endeffector in accordance with various embodiments can comprise electrodesconfigured to heat and seal the tissue. Also, for instance, an endeffector in accordance with certain embodiments can apply vibrationalenergy to seal the tissue.

Many of the surgical instrument systems described herein are motivatedby an electric motor; however, the surgical instrument systems describedherein can be motivated in any suitable manner. In various instances,the surgical instrument systems described herein can be motivated by amanually-operated trigger, for example. In certain instances, the motorsdisclosed herein may comprise a portion or portions of a roboticallycontrolled system. Moreover, any of the end effectors and/or toolassemblies disclosed herein can be utilized with a robotic surgicalinstrument system. U.S. patent application Ser. No. 13/118,241, entitledSURGICAL STAPLING INSTRUMENTS WITH ROTATABLE STAPLE DEPLOYMENTARRANGEMENTS, now U.S. Pat. No. 9,072,535, for example, disclosesseveral examples of a robotic surgical instrument system in greaterdetail.

The entire disclosures of:

U.S. Pat. No. 5,403,312, entitled ELECTROSURGICAL HEMOSTATIC DEVICE,which issued on Apr. 4, 1995;

U.S. Pat. No. 7,000,818, entitled SURGICAL STAPLING INSTRUMENT HAVINGSEPARATE DISTINCT CLOSING AND FIRING SYSTEMS, which issued on Feb. 21,2006;

U.S. Pat. No. 7,422,139, entitled MOTOR-DRIVEN SURGICAL CUTTING ANDFASTENING INSTRUMENT WITH TACTILE POSITION FEEDBACK, which issued onSep. 9, 2008;

U.S. Pat. No. 7,464,849, entitled ELECTRO-MECHANICAL SURGICAL INSTRUMENTWITH CLOSURE SYSTEM AND ANVIL ALIGNMENT COMPONENTS, which issued on Dec.16, 2008;

U.S. Pat. No. 7,670,334, entitled SURGICAL INSTRUMENT HAVING ANARTICULATING END EFFECTOR, which issued on Mar. 2, 2010;

U.S. Pat. No. 7,753,245, entitled SURGICAL STAPLING INSTRUMENTS, whichissued on Jul. 13, 2010;

U.S. Pat. No. 8,393,514, entitled SELECTIVELY ORIENTABLE IMPLANTABLEFASTENER CARTRIDGE, which issued on Mar. 12, 2013;

U.S. patent application Ser. No. 11/343,803, entitled SURGICALINSTRUMENT HAVING RECORDING CAPABILITIES, now U.S. Pat. No. 7,845,537;

U.S. patent application Ser. No. 12/031,573, entitled SURGICAL CUTTINGAND FASTENING INSTRUMENT HAVING RF ELECTRODES, filed Feb. 14, 2008;

U.S. patent application Ser. No. 12/031,873, entitled END EFFECTORS FORA SURGICAL CUTTING AND STAPLING INSTRUMENT, filed Feb. 15, 2008, nowU.S. Pat. No. 7,980,443;

U.S. patent application Ser. No. 12/235,782, entitled MOTOR-DRIVENSURGICAL CUTTING INSTRUMENT, now U.S. Pat. No. 8,210,411;

U.S. patent application Ser. No. 12/235,972, entitled MOTORIZED SURGICALINSTRUMENT, now U.S. Pat. No. 9,050,083;

U.S. patent application Ser. No. 12/249,117, entitled POWERED SURGICALCUTTING AND STAPLING APPARATUS WITH MANUALLY RETRACTABLE FIRING SYSTEM,now U.S. Pat. No. 8,608,045;

U.S. patent application Ser. No. 12/647,100, entitled MOTOR-DRIVENSURGICAL CUTTING INSTRUMENT WITH ELECTRIC ACTUATOR DIRECTIONAL CONTROLASSEMBLY, filed Dec. 24, 2009, now U.S. Pat. No. 8,220,688;

U.S. patent application Ser. No. 12/893,461, entitled STAPLE CARTRIDGE,filed Sep. 29, 2012, now U.S. Pat. No. 8,733,613;

U.S. patent application Ser. No. 13/036,647, entitled SURGICAL STAPLINGINSTRUMENT, filed Feb. 28, 2011, now U.S. Pat. No. 8,561,870;

U.S. patent application Ser. No. 13/118,241, entitled SURGICAL STAPLINGINSTRUMENTS WITH ROTATABLE STAPLE DEPLOYMENT ARRANGEMENTS, now U.S. Pat.No. 9,072,535;

U.S. patent application Ser. No. 13/524,049, entitled ARTICULATABLESURGICAL INSTRUMENT COMPRISING A FIRING DRIVE, filed on Jun. 15, 2012,now U.S. Pat. No. 9,101,358;

U.S. patent application Ser. No. 13/800,025, entitled STAPLE CARTRIDGETISSUE THICKNESS SENSOR SYSTEM, filed on Mar. 13, 2013, now U.S. Pat.No. 9,345,481;

U.S. patent application Ser. No. 13/800,067, entitled STAPLE CARTRIDGETISSUE THICKNESS SENSOR SYSTEM, filed on Mar. 13, 2013, now U.S. PatentApplication Publication No. 2014/0263552;

U.S. Patent Application Publication No. 2007/0175955, entitled SURGICALCUTTING AND FASTENING INSTRUMENT WITH CLOSURE TRIGGER LOCKING MECHANISM,filed Jan. 31, 2006; and

U.S. Patent Application Publication No. 2010/0264194, entitled SURGICALSTAPLING INSTRUMENT WITH AN ARTICULATABLE END EFFECTOR, filed Apr. 22,2010, now U.S. Pat. No. 8,308,040, are hereby incorporated by referenceherein.

Although various devices have been described herein in connection withcertain embodiments, modifications and variations to those embodimentsmay be implemented. Particular features, structures, or characteristicsmay be combined in any suitable manner in one or more embodiments. Thus,the particular features, structures, or characteristics illustrated ordescribed in connection with one embodiment may be combined in whole orin part, with the features, structures or characteristics of one or moreother embodiments without limitation. Also, where materials aredisclosed for certain components, other materials may be used.Furthermore, according to various embodiments, a single component may bereplaced by multiple components, and multiple components may be replacedby a single component, to perform a given function or functions. Theforegoing description and following claims are intended to cover allsuch modification and variations.

The devices disclosed herein can be designed to be disposed of after asingle use, or they can be designed to be used multiple times. In eithercase, however, a device can be reconditioned for reuse after at leastone use. Reconditioning can include any combination of the stepsincluding, but not limited to, the disassembly of the device, followedby cleaning or replacement of particular pieces of the device, andsubsequent reassembly of the device. In particular, a reconditioningfacility and/or surgical team can disassemble a device and, aftercleaning and/or replacing particular parts of the device, the device canbe reassembled for subsequent use. Those skilled in the art willappreciate that reconditioning of a device can utilize a variety oftechniques for disassembly, cleaning/replacement, and reassembly. Use ofsuch techniques, and the resulting reconditioned device, are all withinthe scope of the present application.

The devices disclosed herein may be processed before surgery. First, anew or used instrument may be obtained and, when necessary, cleaned. Theinstrument may then be sterilized. In one sterilization technique, theinstrument is placed in a closed and sealed container, such as a plasticor TYVEK bag. The container and instrument may then be placed in a fieldof radiation that can penetrate the container, such as gamma radiation,x-rays, and/or high-energy electrons. The radiation may kill bacteria onthe instrument and in the container. The sterilized instrument may thenbe stored in the sterile container. The sealed container may keep theinstrument sterile until it is opened in a medical facility. A devicemay also be sterilized using any other technique known in the art,including but not limited to beta radiation, gamma radiation, ethyleneoxide, plasma peroxide, and/or steam.

While this invention has been described as having exemplary designs, thepresent invention may be further modified within the spirit and scope ofthe disclosure. This application is therefore intended to cover anyvariations, uses, or adaptations of the invention using its generalprinciples.

What is claimed is:
 1. A surgical instrument, comprising: an elongateshaft; a surgical end effector coupled to said elongate shaft by anarticulation joint, wherein said articulation joint is configured tofacilitate selective articulation of said surgical end effector relativeto said elongate shaft, and wherein said surgical end effectorcomprises: a first jaw; a second jaw, wherein said second jaw isconfigured to move relative to said first jaw between an open positionand a closed position; and a firing member supported for axial travelwithin said surgical end effector between a starting position and anending position, and wherein said surgical instrument further comprises:an upper flexible spine assembly attached to a top portion of saidfiring member; a lower flexible spine assembly attached to a bottomportion of said firing member; and a rotary drive member, wherein saidrotary drive member operably interfaces with said upper flexible spineassembly at an upper location, wherein said rotary drive member operablyinterfaces with said lower flexible spine assembly at a lower location,wherein said upper location and said lower location are distal to saidarticulation joint, and wherein said rotary drive member causes saidupper flexible spine assembly and said lower flexible spine assembly toapply axial drive motions to said firing member to move said firingmember between said starting position and said ending position.
 2. Thesurgical instrument of claim 1, wherein said rotary drive member iscentrally disposed between said upper flexible spine assembly and saidlower flexible spine assembly.
 3. The surgical instrument of claim 1,wherein said upper flexible spine assembly comprises an upper series ofupper vertebra members that are loosely coupled together, and whereinsaid lower flexible spine assembly comprises a lower series of lowervertebra members that are loosely coupled together.
 4. The surgicalinstrument of claim 3, wherein said upper vertebra members are movablysupported relative to each other by an upper flexible coupler memberthat is coupled to said top portion of said firing member and extendsthrough each said upper vertebra member, and wherein said lower vertebramembers are movably supported relative to each other by a lower flexiblecoupler member that is coupled to said bottom portion of said firingmember and extends through each lower vertebra member.
 5. The surgicalinstrument of claim 4, wherein each said upper vertebra membercomprises: an upper vertebra body portion, wherein said upper vertebrabody portion defines an upper proximal end and an upper distal end; anupper hollow passage in said upper vertebra body portion, wherein saidupper hollow passage extends through said upper vertebra body portionbetween said upper proximal end and said upper distal end to permit saidupper flexible coupler member to extend therethrough; an upper proximalmating feature on said upper proximal end; an upper distal matingfeature on said upper distal end, wherein said upper proximal matingfeature on each said upper vertebra member is configured to movablyinterface with said upper distal mating feature on an adjacent saidupper vertebra member; and an upper vertebra drive feature configured tooperably engage said rotary drive member.
 6. The surgical instrument ofclaim 5, wherein said upper proximal mating feature comprises an upperconcave recess in said upper proximal end of said upper vertebra bodyportion, and wherein said upper distal mating feature comprises an upperconvex protrusion on said upper distal end of said upper vertebra bodyportion, wherein said upper convex protrusion on each said uppervertebra member is sized and shaped to matingly engage said upperconcave recess in said adjacent said upper vertebra member.
 7. Thesurgical instrument of claim 5, wherein each said lower vertebra membercomprises: a lower vertebra body portion, wherein said lower vertebrabody portion defines a lower proximal end and a lower distal end; alower hollow passage in said lower vertebra body portion, wherein saidlower hollow passage extends through said lower vertebra body portionbetween said lower proximal end and said lower distal end to permit saidlower flexible coupler member to extend therethrough; a lower proximalmating feature on said lower proximal end; a lower distal mating featureon said lower distal end, wherein said lower proximal mating feature oneach said lower vertebra member is configured to movably interface withsaid lower distal mating feature on an adjacent said lower vertebramember; and a lower vertebra drive feature configured to operably engagesaid rotary drive member.
 8. The surgical instrument of claim 7, whereinsaid lower proximal mating feature comprises a lower concave recess insaid lower proximal end of said lower vertebra body portion, and whereinsaid lower distal mating feature comprises a lower convex protrusion onsaid lower distal end of said lower vertebra body portion, wherein saidlower convex protrusion on each said lower vertebra member is sized andshaped to matingly engage said lower concave recess in an adjoining saidlower vertebra member.
 9. The surgical instrument of claim 7, whereinsaid upper vertebra drive feature comprises an upper tooth configured tointerface with said rotary drive member, and wherein said lower vertebradrive feature comprises a lower tooth configured to interface with saidrotary drive member.
 10. The surgical instrument of claim 9, whereinsaid rotary drive member comprises: a rotary body portion; and a helicaldrive member on an external surface of said rotary body portion, whereinsaid helical drive member is configured to engage an upper helicalsurface formed on each said upper tooth and a lower helical surface oneach said lower tooth.
 11. The surgical instrument of claim 4, furthercomprising: an upper vertebra biaser configured to apply a continuousupper compression to said upper series of upper vertebra members toretain said upper vertebra members in said upper series of uppervertebra members in movable contact with each other; and a lowervertebra biaser configured to apply a continuous lower compression tosaid lower series of lower vertebra members to retain said lowervertebra members in said lower series of lower vertebra members inmovable contact with each other.
 12. The surgical instrument of claim10, wherein said upper helical surface comprises two different pitches.13. The surgical instrument of claim 4, wherein said upper flexiblecoupler member and said lower flexible coupler member are configured toretract said firing member from a position that is distal to saidstarting position by applying retraction motions to each of said upperflexible coupler member and said lower flexible coupler member in aproximal direction.
 14. The surgical instrument of claim 3, wherein saidarticulation joint comprises an articulation joint length, wherein saidupper series of upper vertebra members comprises an upper series lengththat is greater than or equal to the articulation joint length plus adistance from said starting position to said ending position of saidfiring member, and wherein said lower series of lower vertebra memberscomprises a lower series length that is greater than or equal to thearticulation joint length plus said distance from said starting positionto said ending position of said firing member.
 15. The surgicalinstrument of claim 14, further comprising: an upper sleeve extendingfrom a proximal end of said surgical end effector and spanning saidarticulation joint, wherein said upper sleeve is axially movablerelative to said surgical end effector and is configured to slidablysupport a portion of said upper series of upper vertebra members thatspans said articulation joint; and a lower sleeve extending from saidproximal end of said surgical end effector and spanning saidarticulation joint, wherein said lower sleeve is axially movablerelative to said surgical end effector and is configured to slidablysupport another portion of said lower series of lower vertebra membersthat spans said articulation joint.
 16. A surgical instrument,comprising: an elongate shaft; a surgical end effector coupled to saidelongate shaft by an articulation joint, wherein said articulation jointis configured to facilitate selective articulation of said surgical endeffector relative to said elongate shaft, and wherein said surgical endeffector comprises a firing member supported for axial travel withinsaid surgical end effector between a starting position and an endingposition; a rotary drive member rotatably supported distal to saidarticulation joint; an upper longitudinally-segmented nut assemblyattached to a top portion of said firing member, wherein said upperlongitudinally-segmented nut assembly is in threaded engagement withsaid rotary drive member at an upper location that is distal to saidarticulation joint such that rotation of said rotary drive member causessaid upper longitudinally-segmented nut assembly to apply an upper axialdrive motion to said firing member, and wherein said upperlongitudinally-segmented nut assembly is flexible to accommodate saidarticulation of said surgical end effector; and a lowerlongitudinally-segmented nut assembly attached to a bottom portion ofsaid firing member, wherein said lower longitudinally-segmented nutassembly is in threaded engagement with said rotary drive member at alower location that is distal to said articulation joint such thatrotation of said rotary drive member causes said lowerlongitudinally-segmented nut assembly to apply a lower axial drivemotion to said firing member, and wherein said lowerlongitudinally-segmented nut assembly is flexible to accommodate saidarticulation of said surgical end effector.
 17. The surgical instrumentof claim 16, wherein said upper longitudinally-segmented nut assemblycomprises an upper series of upper vertebra members, wherein said uppervertebra members are movably supported relative to each other by anupper flexible coupler member that is coupled to said top portion ofsaid firing member and extends through each said upper vertebra member,and wherein said lower longitudinally-segmented nut assembly comprises alower series of lower vertebra members, wherein said lower vertebramembers are movably supported relative to each other by a lower flexiblecoupler member that is coupled to said bottom portion of said firingmember and extends through each lower vertebra member.
 18. The surgicalinstrument of claim 17, wherein said rotary drive member comprises ahelical thread comprising at least two different pitches.
 19. Thesurgical instrument of claim 17, further comprising means for permittingsaid upper vertebra members and said lower vertebra members traversingsaid articulation joint to move out of axial alignment whilefacilitating serial threaded engagement with said rotary drive member.20. A surgical instrument, comprising: an elongate shaft; a surgical endeffector coupled to said elongate shaft by an articulation joint,wherein said articulation joint is configured to facilitate selectivearticulation of said surgical end effector relative to said elongateshaft, and wherein said surgical end effector comprises a firing membersupported for axial travel within said surgical end effector between astarting position and an ending position; a rotary drive memberrotatably supported distal to said articulation joint; and a flexibledrive assembly supported by said elongate shaft, wherein said flexibledrive assembly axially traverses said articulation joint and isconfigured to accommodate articulation of said surgical end effectorabout said articulation joint, and wherein said flexible drive assemblyis in threaded engagement with said rotary drive member at a drivelocation that is distal to said articulation joint such that rotation ofsaid rotary drive member causes said flexible drive assembly to apply anaxial drive motion to said firing member.